Academic Interests
Statistical theory, statistical biology
Courses taught
Background
 Professor of statistics, Department of economics, University of Oslo, 1984
 Professor of statistics, University of Tromsø, 19811983
 Associate professor of statistics, University of Tromsø, 19761981
 Phd. (statistics), University of California  Berkeley, 1974
 Assistant professor, Department of mathematics, University of Oslo, 19711973
 Assistant professor, Department of economics, University of Oslo, 19691971
 Research Assistant, Department of mathematics, University of Oslo, 19671968
 Cand. real (statistics), University of Oslo, 1962
Positions held
 Senior scientist, Centre for Ecological and Evolutionary Synthesis (CEES), 2003
 Member of the board, The Norwegian Academy of Science and Letters, 20022008
 Chair, Scandinavian Journal of Statistics, 19992004
 Member, The Norwegian Academy of Science and Letters, 1998
 Senior scientist, Norwegian Computing Center, 19982009
 Member of the board, Scandinavian Journal of Statistics, 19952004
 Delegate, International Whaling Commission, 1990
 Member, Scientific Committee of the International Whaling Committe, 1989
 Senior scientist, Norwegian Computing Center, 19861996
 Member, European Regional Committee, Bernoulli Society, 19861990
 Senior scientist, Statistics Norway, 19831984
 Associate Editor, Scandinavian Journal of Statistics, 19811990
 Chair, Norwegian Statistical Association, 19711972
Tags:
Economics,
Econometrics
Publications
 Lee Hsiang Liow, Hans Julius Skaug, Torbjørn Ergon and Tore Schweder "Global occurrence trajectories of microfossils: environmental volatility and the rise and fall of individual species" Paleobiology 36; 2010: 224252
 Tore Schweder, Dinara Sadykova, David Rugh and William Koski "Population Estimates From Aerial Photographic Surveys of Naturally and Variably Marked Bowhead Whales" Journal of Agricultural Biological and Environmental Statistics 2010 15: 119
 Per Erik Jorde, Tore Schweder, JW Bickham, GH Givens, R. Suydam, D. Hunter and Nils Christian Stenseth, "Detecting genetic structure in migrating bowhead whales off the coast of Barrow, Alaska," Molecular Ecology, 2007: 19932004
 Tore Schweder and Rasmus Plenge Waagepetersen, "Likelihoodbased inference for clustered line transect data," Journal of Agricultural, Biological, and Environmental Statistics, 2006, 11:264279
 Hans J. Skaug, Nils Øien, Tore Schweder and Gjermund Bøthun, "Abundance of minke whales (Balaenoptera acutorostrata) in the Northeast Atlantic: variability in time and space," Can. J. Fish. Aquat. Sci. 61, 2004, 870886
 Tore Schweder and Nils Lid Hjort, "Frequentist analogues of priors and posteriors," In B.P. Stigum, Econometrics and the philosophy of economics, Princeton University Press, 2003, 285317.
 Tore Schweder,"Abundance estimation from photoidentification data: confidence distributions and reduced likelihood for bowhead whales off Alaska," Biometrics 59, 2003, 976985
 Tore Schweder and Nils Lid Hjort, "Confidence and likelihood," Scandinavian Journal of Statistics 29, 2002, 309332
 Olaf Gjerløw Aasland, Øvind Ekeberg and Tore Schweder, "Suicide rates from 1960 to 1989 in Norwegian physicians compared with other educational groups," Social Science and Medicine 52, 2001, 259265
 Tore Schweder and Emil Spjøtvoll, "Pvalue plots to evaluate many tests simultaneously," Biometrika, 1982, 69: 493502
 Tore Schweder, "Composable Markov Processes," Journal of Applied Probability, 1970, 7: 40010

De Blasi, Pierpaolo & Schweder, Tore (2017). Confidence distributions from likelihoods by median bias correction. Journal of Statistical Planning and Inference.
ISSN 03783758.
195, s 35 46 . doi:
10.1016/j.jspi.2017.09.010

Diekert, Florian Klaus & Schweder, Tore (2017). Disentangling Effects of Policy Reform and Environmental Changes in the Norwegian Coastal Fishery for Cod. Land Economics.
ISSN 00237639.
93(4), s 689 709 . doi:
10.3368/le.93.4.689
Full text in Research Archive.

Hjort, Nils Lid & Schweder, Tore (2017). Confidence distributions and related themes. Journal of Statistical Planning and Inference.
ISSN 03783758.
195, s 1 13 . doi:
10.1016/j.jspi.2017.09.017

Schweder, Tore (2017). Confidence is epistemic probability for empirical science. Journal of Statistical Planning and Inference.
ISSN 03783758.
. doi:
10.1016/j.jspi.2017.09.016

De Blasio, Fabio V; Liow, Lee Hsiang; Schweder, Tore & De Blasio, Birgitte Freiesleben (2015). A model for global diversity in response to temperature change over geological time scales, with reference to planktic organisms. Journal of Theoretical Biology.
ISSN 00225193.
365, s 445 456 . doi:
10.1016/j.jtbi.2014.10.031

Koyano, Hitoshi; Serbezov, Dimitar; Kishino, Hirohisa & Schweder, Tore (2013). Fractional parentage analysis and a scalefree reproductive network of brown trout. Journal of Theoretical Biology.
ISSN 00225193.
336, s 18 35 . doi:
10.1016/j.jtbi.2013.06.038
Show summary
In this study, we developed a method of fractional parentage analysis using microsatellite markers. We propose a method for calculating parentage probability, which considers missing data and genotyping errors due to null alleles and other causes, by regarding observed alleles as realizations of random variables which take values in the set of alleles at the locus and developing a method for simultaneously estimating the true and null allele frequencies of all alleles at each locus. We then applied our proposed method to a large sample collected from a wild population of brown trout (Salmo trutta). On analyzing the data using our method, we found that the reproductive success of brown trout obeyed a power law, indicating that when the parentoffspring relationship is regarded as a link, the reproductive system of brown trout is a scalefree network. Characteristics of the reproductive network of brown trout include individuals with large bodies as hubs in the network and different power exponents of degree distributions between males and females.

Kraugerud, Marianne; Aleksandersen, Mona; Nyengaard, JR; Østby, Gunn Charlotte; Gutleb, Arno; Dahl, Ellen; Berg, Vidar; Farstad, Wenche; Schweder, Tore; Skåre, Janneche Utne & Ropstad, Erik (2012). In utero and lactational exposure to PCB 118 and PCB 153 alter ovarian follicular dynamics and GnRHinduced luteinizing hormone secretion in female lambs. Environmental Toxicology.
ISSN 15204081.
27(11), s 623 634 . doi:
10.1002/tox.20679

Reitan, Trond; Schweder, Tore & Henderiks, Jorijntje (2012). Phenotypic evolution studied by layered stochastic differential equations. Annals of Applied Statistics.
ISSN 19326157.
6, s 1531 1551 . doi:
10.1214/12AOAS559
Full text in Research Archive.

Schweder, Tore & Preisler, Haiganoush (2012). Introductory comments to some applied papers by David R. Brillinger, In Peter Guttorp & David R. Brillinger (ed.),
Selected works of David Brillinger.
Springer Science+Business Media B.V..
ISBN 9781461413431.
Part III Population biology and environment.
s 325
 333

Schweder, Tore & Sadykova, Dinara (2012). Information dynamics and optimal sampling in capturerecapture. Biometrika.
ISSN 00063444.
99(2), s 488 493 . doi:
10.1093/biomet/ass001
Show summary
The build up of information in a continued capturerecapture experiment of simple random sampling of an open population is studied by predicting the conditional approximate Fisher information for abundance in data from one survey given the previous data. By neglecting the stochasticity in survival, a simple approximate likelihood is obtained. Optimal temporal allocation of a given total effort is found by numerical optimization for various objective functions based on the approximate Fisher information. For aerial photographic surveys of bowhead whales, the performance of estimates of abundance and of demographic parameters is compared between constant yearly survey effort and nominally optimal sampling by simulating a realistic model over 50 years.

Sadykova, Dinara; Skurdal, Jostein; Hessen, Dag Olav & Schweder, Tore (2011). Saving the largest makes a difference: exploring effects of harvest regulations by model simulations for noble crayfish, Astacus astacus. Fisheries Management and Ecology.
ISSN 0969997X.
18(4), s 307 313 . doi:
10.1111/j.13652400.2011.00784.x

Liow, Lee Hsiang; Skaug, Hans Julius; Ergon, Torbjørn H. & Schweder, Tore (2010). Global occurrence trajectories of microfossils: environmental volatility and the rise and fall of individual species. Paleobiology.
ISSN 00948373.
36(2), s 224 252 . doi:
10.1666/08080.1

Schweder, Tore; Sadykova, Dinara; Rugh, David & Koski, William (2010). Population Estimates From Aerial Photographic Surveys of Naturally and Variably Marked Bowhead Whales. Journal of Agricultural Biological and Environmental Statistics.
ISSN 10857117.
15(1), s 1 19 . doi:
10.1007/s1325300900021
Show summary
Abundance, mortality and population growth of bowhead whales are estimated from captures of 4894 putatively different individuals obtained from ten years of systematic photographic surveys conducted during the spring migration when most of the BeringChukchiBeaufort population of bowheads migrates past Point Barrow, Alaska. A stringent matching protocol designed to prevent false positive matches of the naturally but variably marked individuals led to 42 resightings between years. The flip side of this stringency is a presence false negative, i.e. some true recaptures are not recognized as such The problem of false negatives is addressed by modeling the capture process and the matching process. The captures of an individual are assumed to follow a Poisson process with intensity depending stochastically on the individual whale and on the year. The probability of successfully matching a capture to a previous capture is estimated by logistic regression on the degree of marking and image quality. Individuals are recruited by the PellaTomlinson population model, assuming their mortality rate is constant. An approximate likelihood is maximized. Bias, which is mainly due to false negative matches, is corrected using bootstrapping, and confidence curves in agreement with previous results are obtained for key parameters.

Sadykova, Dinara & Schweder, Tore (2009). Migration ranks for bowhead whales (Balaena mysticetus) at Barrow in spring. Journal of Cetacean Research and Management.
ISSN 15610713.
11(1), s 17 22

Aldrin, Magne; Huseby, Ragnar Bang & Schweder, Tore (2008). A note on tuning the Catch Limit Algorithm for commercial baleen whaling. Journal of Cetacean Research and Management.
ISSN 15610713.
10(3), s 191 194
Show summary
The Catch Limit Algorithm for commercial baleen whaling developed by the International Whaling Commission converges slowly to a steady depletion (proportion of carrying capacity), and consequently 300 years of management is proposed as horizon for tuning and computer simulation. Longterm depletion is rather insensitive to the parameter currently used for tuning, and an alternative control parameter is suggested for this purpose.

Jorde, Per Erik; Schweder, Tore; Bickham, JW; Givens, GH; Suydam, R; Hunter, D & Stenseth, Nils Christian (2007). Detecting genetic structure in migrating bowhead whales off the coast of Barrow, Alaska. Molecular Ecology.
ISSN 09621083.
16, s 1993 2004 . doi:
10.1111/j.1365294X.2007.03268.x

Schweder, Tore (2007). Confidence nets for curves, In Vijay Nair (ed.),
Advances in statistical modeling and inference. Essays in honor of Kjell A. Doksum.
World Scientific.
ISBN 9812703691.
Chapter 29.

Waagepetersen, Rasmus & Schweder, Tore (2006). LikelihoodBased Inference for Clustered Line Transect Data. Journal of Agricultural Biological and Environmental Statistics.
ISSN 10857117.
11, s 264 279
Show summary
The uncertainty in estimation of spatial animal density from line transect surveys depends on the degree of spatial clustering in the animal population. To quantify the clustering we model line transect data as independent thinnings of spatial shotnoise Cox processes. Likelihoodbased inference is implemented using Markov chain Monte Carlo (MCMC) methods to obtain efficient estimates of spatial clustering parameters. Uncertainty is addressed using parametric bootstrap or by consideration of posterior distributions in a Bayesian setting. Maximum likelihood estimation and Bayesian inference are compared in an example concerning minke whales in the northeast Atlantic.

Schweder, Tore (2006). The Scenario Barents Sea study: a case of minimal realistic modelling to compare management strategies for marine ecosystems, In Ian Boyd; Sarah Wanless & C.J. Camphuysen (ed.),
Top Predators in Marine Ecosystems. Their Role in Monitoring and Management.
Cambridge University Press.
ISBN 9780521847735.
21.
s 310
 323

Skaug, Hans Julius; Øien, Nils; Schweder, Tore & Bøthun, G (2004). Abundance of minke whales (Balaenoptera acutorostata) in the Northeast Atlantic: variability in time and space. Canadian Journal of Fisheries and Aquatic Sciences.
ISSN 0706652X.
61, s 870 886

Skaug, Hans Julius; Øien, Nils; Schweder, Tore & Bøthun, Gjermund (2004). Abundance of minke whales (Balaenoptera acutorostrata) in the Northeastern Atlantic. Canadian Journal of Fisheries and Aquatic Sciences.
ISSN 0706652X.
61, s 870 886

Schweder, Tore (2003). Abundance estimation from photoidentification data: confidence distributions and reduced likelihood for bowhead whales off Alaska. Biometrics.
ISSN 0006341X.
59, s 976 985

Schweder, Tore (2003). Discussion of Kardaun, O.J.W.F, Salomé, D., Schaafsma, W., Steerneman, A.G.M., Willems, J.C. and Cox, D.R. Reflections on Fourteen Cryptic Issues Concerning the Nature of Statistical Inference. International Statistical Review.
ISSN 03067734.
71, s 303 307

Schweder, Tore (2003). Integrative fish stock assessment by frequentist methods: confidence distributions and likelihoods for bowhead whales. Scientia Marina.
ISSN 02148358.
67, s 89 97

Schweder, Tore & Hjort, Nils Lid (2003). Frequentist analogues of priors and posteriors, In Bernt Petter Stigum (ed.),
Econometrics and the Philosophy of Economics. TheoryData Confrontations in Economics.
Princeton University Press.
ISBN 0691113009.
Chapter 13.
s 285
 317

Aldrin, Magne; Holden, Marit & Schweder, Tore (2003). Comment on Cowling's "Spatial Methods for Line Transect Surveys". Biometrics.
ISSN 0006341X.
59, s 186 188
Show summary
We consider the problem of estimating the parameters of a twodimensional NeymanScott process, from data collected through a line transect survey. Cowling (1998) suggested an estimation method based on a onedimensional Kfunction along the transect line. However, her expression for the theoretical Kfunction is wrong. In this paper, we correct her Kfunction.

Schweder, Tore (2003). Abundance estimation from multiple photo surveys: Confidence distributions and reduced likelihoods for bowhead whales off Alaska. Biometrics.
ISSN 0006341X.
59, s 974 983

Høst, Gudmund; Berg, Erlend; Schweder, Tore & Tjelmeland, Sigurd (2002). A Gamma/Direchlet model for estimating uncertainty in agespecific abundance of Norwegian springspawning herring. ICES Journal of Marine Science.
ISSN 10543139.
59, s 737 748 . doi:
10.1006/jmsc.2001.1176
Show summary
An approach to estimating the statistical uncertainty in agespecific abundance of Norwegian springspawning herring is presented. The method is applied to data from a survey on the overwintering stock in the Vestfjord system in northern Norway in December 1996. It is based on building separate statistical models for acoustic and biological data. The acoustic data are modelled as a gammatransformed spatial random field and fitted to echo readings from the survey. The biological data are fitted to a twostage model using multinomial sampling from Dirichletdistributed age proportions. Uncertainty in the abundance by age distribution is obtained by bootstrapping. Previous assessments have a priori taken the abundance by age from a skewed distribution, such as gamma or lognormal families. In contrast, this analysis results in an estimated abundance by age that seems symmetric and does not display heavy tails.

Schweder, Tore (2002). Large Structured Models in Applied Sciences; Challenges for Statistics. Scandinavian Journal of Statistics.
ISSN 03036898.
29(2), s 189 191

Schweder, Tore (2002). Large structured models in applied science; challenges for statistics. Scandinavian Journal of Statistics.
ISSN 03036898.
Vol. 29, s 189 191

Schweder, Tore & Hjort, Nils Lid (2002). Confidence and likehood. Scandinavian Journal of Statistics.
ISSN 03036898.
Vol. 29, s 309 332

Schweder, Tore & Hjort, Nils Lid (2002). Confidence and likelihood. Scandinavian Journal of Statistics.
ISSN 03036898.
29(2), s 309 332
Show summary
Confidence intervals for a single parameter are spanned by quantiles of a confidence distribution, and onesided pvalues are cumulative confidences. Confidence distributions are thus a unifying format for representing frequentist inference for a single parameter. The confidence distribution, which depends on data, is exact (unbiased) when its cumulative distribution function evaluated at the true parameter is uniformly distributed over the unit interval. A new version of the NeymanPearson lemma is given, showing that the confidence distribution based on the natural statistic in exponential models with continuous data is less dispersed than all other confidence distributions, regardless of how dispersion is measured. Approximations are necessary for discrete data, and also in many models with nuisance parameters. Approximate pivots might then be useful. A pivot based on a scalar statistic determines a likelihood in the parameter of interest along with a confidence distribution. This proper likelihood is reduced of all nuisance parameters, and is appropriate for metaanalysis and updating of information. The reduced likelihood is generally different from the confidence density. Confidence distributions and reduced likelihoods are rooted in FisherNeyman statistics. This frequentist methodology has many of the Bayesian attractions, and the two approaches are briefly compared. Concepts, methods and techniques of this brand of FisherNeyman statistics are presented. Asymptotics and bootstrapping are used to find pivots and their distributions, and hence reduced likelihoods and confidence distributions. A simple form of inverting bootstrap distributions to approximate pivots of the abc type is proposed. Our material is illustrated in a number of examples and in an application to multiple capture data for bowhead whales.

Aasland, Olaf Gjerløw; Ekeberg, Øivind & Schweder, Tore (2001). Suicide rates from 1960 to 1989 in Norwegian physicians compared with other educational groups. Social Science and Medicine.
ISSN 02779536.
52(2), s 259 265
Show summary
There were 82 registered physician suicides, of which 9 were female, 265 suicides by persons with other university education, and 11,165 by persons with no university education. Suicide rate is measured in number of deaths per 100,000 person years. Crude suicide rates were 47.7 (95% CI 37.760.4) for male physicians, 20.1 (17.722.9) for other male university graduates, and 22.7 (22.223.2) for men with no university education. The corresponding figures for females were 32.3 (15.863.7), 13.0 (8.419.8) and 7.7 (7.58.0). Both for males and females, suicide rates, controlled for age and period, were significantly higher for physicians than for persons with other or no university education. Poisson modelling showed that the risk of suicide for male physicians has the same age pattern as for other males with higher education. In 198589 the suicide rate for male physicians increased nearly linearly from about 35 at the age 3540 to about 100 at the age 7579, which was almost three times higher than for the other male university graduates. For the age group 5054 the estimated rate increases from about 50 in 196064 to about 90 in 198589. For the female physicians, the low number of cases prevents reliable estimation of trends. For male physicians, the trend from 1960 to 1989 is increasing. The estimated risk for a single physician to commit suicide was almost 5 times that of a married or cohabitant colleague. For 52% of the male and 85% of the female physicians the suicide method was poisoning. This is about twice the rates in the general population.

Aasland, Olaf Gjerløw; Ekeberg, Øivind & Schweder, Tore (2001). Suicide rates from 1960 to 1989 in Norwegian physicians compared with other occupational groups. Social Science and Medicine.
ISSN 02779536.
52, s 259 265
Show summary
The aim of the present study is to compare suicide rates between 1960 and 1989 for Norwegian physicians with corresponding rates for other Norwegians with and without university education, by age, gender, and fiveyear period, based on death certificates for all Norwegians who died in the period 19601989. There were 82 registered physician suicides, of which 9 were female, 265 suicides by persons with other university education, and 11,165 by persons with no university education. Suicide rate is measured in number of deaths per 100,000 person years. Crude suicide rates were 47.7 (95% CI 37.760.4) for male physicians, 20.1 (17.722.9) for other male university graduates, and 22.7 (22.223.2) for men with no university education. The corresponding figures for females were 32.3 (15.863.7), 13.0 (8.419.8) and 7.7 (7.58.0). Both for males and females, suicide rates, controlled for age and period, were significantly higher for physicians than for persons with other or no university education. Poisson modelling showed that the risk of suicide for male physicians has the same age pattern as for other males with higher education. In 198589 the suicide rate for male physicians increased nearly linearly from about 35 at the age 3540 to about 100 at the age 7579, which was almost three times higher than for the other male university graduates. For the age group 5054 the estimated rate increases from about 50 in 196064 to about 90 in 198589. For the female physicians, the low number of cases prevents reliable estimation of trends. For male physicians, the trend from 1960 to 1989 is increasing. The estimated risk for a single physician to commit suicide was almost 5 times that of a married or cohabitant colleague. For 52% of the male and 85% of the female physicians the suicide method was poisoning. This is about twice the rates in the general population.

Schweder, Tore (2001). Protecting whales by distorting uncertainty: nonprecautionary mismanagement?. Fisheries Research.
ISSN 01657836.
52(3), s 217 225
Show summary
Precautionary management is based on science, and is incompatible with large fluctuations in the management regime. Whaling is managed by the International Whaling Commission, and has seen large fluctuations. It is argued that both the period of intense Antarctic whaling and the current period of protectionism have been unduly prolonged by scientists expanding out of proportion the uncertainty surrounding management issues. In the 1950s, uncertainty concerning fin whale stock status and trend was consistently distorted from one quarter, and in the 1990s a minority in the Scientific Committee blocked consensus over the Revised Management Procedure that had been successfully developed by the Committee. In both cases, the political consequence of expanded uncertainty in the science was lack of action, resulting in a continuation of ¿business as usual¿. Extending a period of heavy exploitation longer than the resource can sustain is mismanagement. Extending a period of extreme protectionism when the resource is known to scientists to sustain valuable exploitation is also mismanagement, even from a conservationist point of view. This might, in fact, erode the role of science in management and thus prepare the ground for subsequent overexploitation. Distorting uncertainty by injecting controversy or otherwise expanding uncertainty has contributed to excessive fluctuations in management regimes and consequently in stock abundance. Detrimental fluctuations might continue, since science is side tracked and management now is based on sentiments that might fade.

Schweder, Tore (2001). Skepsisens plass i biologien  om falske funn og fordreid usikkerhet. Biolog.
ISSN 08010722.
3, s 12062012

Schweder, Tore (2000). Distortion of Uncertainty in Science: Antarctic Fin whales in the 1950s. Journal of international wildlife law and policy.
ISSN 13880292.
3(1), s 73 92
Show summary
In the 1950s, the majority of scientists in the International Whaling Commission (IWC) argued that the fin whale was overexploited in the Southern Hemisphere. However, several other scientists throughout the period persistently objected to this view. The scientific controversy attendant to this issue engendered great uncertainty. This uncertainty contributed towards extending the period of excessive whaling, and nearly destroyed the IWC. This papers reviews the fin whale debate in detail, puts the debate in a political perspective, and argues that the intentional injection of controversy for nonscientific reasons in decisionmaking forums, which the author terms "distortion of uncertainty", constitutes an act of scientific miconduct.

Schweder, Tore; Hagen, Gro Synøve & Hatlebakk, Einar (2000). Direct and indirect effects of minke whale abundance on cod and herring fisheries: A scenario experiment for the Greater Barents Sea. NAMMCO scientific publications.
ISSN 15602206.
2, s 120 133
Show summary
To study the pattern of interaction between minke whale (Balaenoptera acutorostrata) abundance and the main fisheries in the Greater Barents Sea, a simulation experiment was carried out. The population model involves 4 species interconnected in a food web: cod (Gadus morhua), capelin (Mallotus villosus), herring (Clupea harengus) and minke whales. Minke whales are preying on cod, capelin and herring; cod are preying on (young) cod, capelin and herring; herring in the Barents Sea are preying on capelin; while capelin is a bottom prey in the model. The consumption function for minke whales is estimated from stomach content data and prey abundance data. The model is dynamic. Minke whale abundances are kept on fixed levels, while recruitment in fish is stochastic. For cod catches, both the direct effect of whales consuming cod, and the indirect effect due to whales competing with cod for food and otherwise altering the ecosystem, are linear and of equal importance. The net effect on the herring fishery is of the same magnitude as the net effect on the cod fishery, with each extra whale reducing the catches of both species by some 5 tonnes.

Schweder, Tore (1999). Line transecting with difficulties; lessons from surveying minke whales, In G.W. Garner; S.C. Amstrup; J.L. Laake; B.F.J. Manly; L.L. McDonald & D.G. Robertson (ed.),
Marine Mammal Survey and Assessment Methods.
A.A.Balkema.
ISBN 9058090434.
s 149
 166
Show summary
Difficulties encountered in line transecting, like missed observations on the track line, discrete cues, heterogeneity in cue strength or sighting efficiency, and measurement errors, might cause estimates of abundance to be biased. Methods for removing bias in abundance estimates based on difficult line transect survey data are considered, with an emphasis on hazard probability modelling and likelihood analysis with simulation as an integral part of the estimation. The shipborn survey of minke whales (Balaenoptera acuturostrata) in the northeastern Atlantic in 1995 was intrinsically difficult. Experiences from this survey and its analysis are reviewed. If the survey had been designed and the data analyzed by traditional line transect methodology, results would be biased negatively by some 85%.

Schweder, Tore & Hagen, Gro Synøve (1999). A note on the cost of instability in whale management. Journal of Cetacean Reserch and Management.
1(2), s 137 140
Show summary
The history of whaling is characterized by considerable variation in management "philosophy". For example, an early period of overexploitation led eventually to the present period of protectionism, and might be followed by a period of excessive catches. Is such instability in longterm management costly? The risk of depletion is clearly increased with increasing instability. If the net production function governing the whale dynamics essentially is convex, it is demonstrated that longterm catches are necessarily smaller the greater the management instability. A simulation experiment is carried out to quantify the loss in whale catches due to "stopgo" instability in whale management. To examine possible costs in terms of fisheries for cod and herring, a multispecies simulation model is used, with minke whales managed by a stochastic stopgo procedure and with cod, herring and capelin managed by VPAtype procedures. In the simulations, whale catches are reduced by increased instability in whale management while longterm catches of cod and herring are unaffected, provided mean whale abundance is kept fixed.

Schweder, Tore; Skaug, Hans J.; Langaas, Mette & Dimakos, Xeni Kristine (1999). Simulated likelihood methods for complex doubleplatform line transect surveys. Biometrics.
ISSN 0006341X.
55, s 678 687
Show summary
The conventional line transect approach of estimating effective search width from the perpendicular distance distribution is inappropriate in certain types of surveys, e.g., when an unknown fraction of the animals on the track line is detected, the animals can be observed only at discrete points in time, there are errors in positional measurements, and covariate heterogeneity exists in detectability. For such situations a hazard probability framework for independent observer surveys is developed. The likelihood of the data, including observed positions of both initial and subsequent observations of animals, is established under the assumption of no measurement errors. To account for measurement errors and possibly other complexities, this likelihood is modified by a function estimated from extensive simulations. This general method of simulated likelihood is explained and the methodology applied to data from a doubleplatform survey of minke whales in the northeastern Atlantic in 1995.

Skaug, Hans Julius & Schweder, Tore (1999). Hazard models for line transect surveys with independent observers. Biometrics.
ISSN 0006341X.
55, s 29 36
Show summary
The likelihood function for data from independent observer line transect surveys is derived, and a hazard model is proposed for the situation where animals are available for detection only at discrete time points. Under the assumption that the time points of availability follow a Poisson point process, we obtain an analytical expression for the detection function. We discuss different criteria for choosing the hazard function and consider in particular two different parametric families of hazard functions. Discrete and continuous hazard models are compared and the robustness of the discrete model is investigated. Finally, the methodology is applied to data from a survey for minke whales in the northeastern Atlantic.

Flaaten, Ola; Salvanes, Anne Gro Vea; Schweder, Tore & Ulltang, Øyvind (1998). Fisheries management under uncertainty  an overview. Fisheries Research.
ISSN 01657836.
37(13), s 1 6

Flaaten, Ola; Salvanes, Anne Gro Vea; Schweder, Tore & Ulltang, Øyvind (1998). Fisheries management under uncertainty  an overview. Fisheries Research.
ISSN 01657836.
37, s 1 6
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Schweder, Tore & Hjort, Nils Lid (2016). Confidence, Likelihood, Probability. Statistical Inference with Confidence Distributions..
Cambridge University Press.
ISBN 9780521861601.
511 s.
View all works in Cristin

Schweder, Tore (2015). Confidence is epistemic probability.

Diekert, Florian Klaus; Schweder, Tore & Lund, Kristen (2014). From OpenAccess to Individual Quotas: Disentangling the Effects of Policy Reform and Environmental Changes in the Norwegian Coastal Cod Fishery. Memorandum from Department of Economics, University of Oslo. 7/2014.

Schweder, Tore & Hjort, Nils Lid (2014). Optimal and approximate likelihood.

Henderiks, Jorijntje; Gerecht, Andrea; Hannisdal, Bjarte; Liow, Lee Hsiang; Reitan, Tore; Schweder, Tore & Edvardsen, Bente (2013). PhytoSCALE project: calibrating phytoplankton cell size as a proxy for climatic adaptation.

Schweder, Tore (2013). Integrating confidence intervals, likelihoods and condence distrubutions.

Schweder, Tore & Hjort, Nils Lid (2013). Confidence Distribution, the Frequentist Distribution Estimator of a Parameter: A Review Discussions. International Statistical Review.
ISSN 03067734.
81(1), s 56 68 . doi:
10.1111/insr.12004

Hjort, Nils Lid & Schweder, Tore (2012). Structure and Uncertainty: Confidence and Likelihood.

Schweder, Tore (2012). Causal sufficiency and Markov Completeness.

Schweder, Tore (2012). Confidence distributions and confidence likelihood: distributional inference without priors.

Schweder, Tore (2012). Confidence distributions and confidence likelihood: distributional inference without priors.

Henderiks, Jorijntje; Hannisdal, Bjarte; Rickaby, Rosalind E. M.; Liow, Lee Hsiang; Reitan, Trond & Schweder, Tore (2010). Phytoplankton size: climatic adaptation and longterm evolution.

Reitan, Trond; Schweder, Tore & Henderiks, Jorijntje (2010). Modelling Phenotypic Evolution by Stochastic Differential Equations.
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In this presentation, we described how to use layered linear stochastic differential equations to model evolutionary processes. This model family was used in order to analyse microfossil data spanning several tens of millions of years.

Witting, Lars & Schweder, Tore (2008). Lower confidence bound on population status from catch sex ratio: applied to minke whales off West Greenland.
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Lower confidence bounds on carrying capacity is estimated by parametric bootstrapping in the case of infinte maximum likelihood estimate.

Schweder, Tore & Sadykova, Dinara (2007). Event history models for capturerecapture surveys with passively marked individuals.

Schweder, Tore & Sadykova, Dinara (2007). Event history models for capturerecapture surveys with passively marked individuals.

Schweder, Tore & Sadykova, Dinara (2007). Rough Modeling of complex photoID data for BCB bowhead whales.

Schweder, Tore; Sadykova, Dinara; Rugh, D.J. & Koski, W.R (2007). Modeling of complex photoID data for BCB bowhead whales.

Aldrin, Magne Tommy; Storvik, Bård & Schweder, Tore (2006). Standardized catch per unit effort in minke whaling in Norwegian waters, 19521983 and 19932004. NRnotat. SAMBA/03/06.

Aldrin, Magne; Huseby, Ragnar Bang & Schweder, Tore (2006). Simulation trials for a retuned Catch Limit Algorithm. NRnotat. SAMBA/10/06.

Aldrin, Magne; Huseby, Ragnar Bang & Schweder, Tore (2006). Variants of the Catch Limit Algorithm. NRnotat. SAMBA/11/06.

Schweder, Tore; Jorde, Per Erik & Stenseth, Nils Christian (2005). Temporal genetic pattern in BCB bowhead whales in the fall migration at Barrow: a reflection of a structured population? IWC/SC/57/BRG10.

Aldrin, Magne & Schweder, Tore (2005). Revision of RMP – Status of ongoing work at the Norwegian Computing Center. IWC/SC/57/RMP3.

Aldrin, Magne & Schweder, Tore (2005). ScenarioC  sluttrapport. NRnotat. SAMBA/13/05.

Hagen, Gro Synøve & Schweder, Tore (2005). Scenario C: A program documentation. NRnotat. SAMBA/04/05.

Jorde, Per Erik; Schweder, Tore & Stenseth, Nils Christian (2004). The BeringChukchiBeaufort stock of bowhead whales: one homogenous population?.

Zhu, Mian; Schweder, Tore & Hagen, Gro Synøve (2004). ScenarioC: The cod predation model. NRnotat. SAMBA/09/04.

Schweder, Tore (2003). Sjangerbrudd eller vitenskapelig uredelighet i Lomborgsaken?. Økonomisk forum.
ISSN 15026108.
8(3), s 1 4

Schweder, Tore (2003). Statistikkens historie i Norge � faktisk uten statistikere?. Tidsskrift for samfunnsforskning.
ISSN 0040716X.
44, s 309 318

Hagen, Gro Synøve; Høst, Gudmund & Schweder, Tore (2003). Harp Seal in the ScenarioC Model. NRnotat. SAMBA/26/03.

Aldrin, Magne; Schweder, Tore & Holden, Marit (2002). Spatial distribution of whales based on the Norwegian Minke Whale Survey 19962001. Ukjent.

Fleischer, Luis A. & Schweder, Tore (2002). Gray whales on their winter grounds in Baja California Sur, México (19801998). Scientific Committee. BRG11.
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Temporal and seasonal patterns of abundance of adults and calves were estimated by generalized linear models from weakly counts obtained from shipborn and aerial surveys.

Hagen, Gro Synøve; Høst, Gudmund & Schweder, Tore (2002). Analyse av replikatdata fra Vestfjorden 2001. NRnotat. SAMBA/23/02.

Schweder, Tore (2002). Forkludring av vitenskapelig usikkerhet  erfaringer fra Hvalfangstkommisjonen. Cicerone.
ISSN 08040508.
s 13 15
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Forskere kan fuske på flere måter. En av dem er å forkludre den vitenskapelige usikkerheten ved å konstruere opp eller provosere fram unødige uenigheter og kontroverser. Dette har skjedd ved flere anledninger i Den internasjonale hvalfangskomisjonen.

Schweder, Tore (2002). Frequentist versions of posteriors and priors.
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Confidence distributions are Neyman's interpretation of Fisher's fiducial distributions. They are the frequentist's analogues of Bayesian priors and posteriors. The quantiles of a confidence distribution are end points of confidence intervals for the parameter in question. To combine a prior confidence distribution with the likelihood of new data, it must be converted to a likelihood summarizing the past data. The two likelihood components are then multiplied together, and posterior confidence distributions are obtained for the parameters of interest, often through a parametric bootstrap experiment. The likelihood related to a confidence distribution is in general different from the confidence density. A version of the NeymanPearson theorem is proved for confidence distributions. The frequentist approach is illustrated on capturerecapture data for bowhead whales, and is compared to the Bayesian approach with respect to bias and other issues

Schweder, Tore (2002). The history of statistics in Norway  told by historians.
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Lie, E. and RollHansen, H. 2001. Faktisk talt  statistikkens historie i Norge (Factually speaking  The history of statistics in Norway), Universitetsforlaget, is written by two historians. I will comment on this book of 481 pages by asking two questions: (i) What is statistics to the historians, and what do they see as the place of statistics in in the shaping of the Norwegian society? And (ii) what have they found that is of particular interest to the general historian of statistics? Among other things, the authors have brought to the light a debate between Anders Kiær who used his representative method (survey sampling) to investigate the costs of introducing a public and universal pension scheme for old and disabled (proposed in 1894), and Jens Hjorth who used actuarial and statistical methods to argue that Kiær's survey gave biased results. Hjorth won the debate, and Kiær became silent about his representative method  while survey sampling was gaining growing attention internationally.

Aldrin, Magne; Holden, Marit & Schweder, Tore (2001). Estimation of a NeymanScott process from line transect data by a onedimensional Kfunction. NRnotat. SAMBA/18/01.

Berg, Erlend; Schweder, Tore & Tvete, Ingunn Fride (2001). Statistisk modellering av kommersielle fangstdata; en illustrasjon basert på trålfangster av torsk i 1999. NRnotat. SAMBA/01/01.

Schweder, Tore (2001). Abundance estimation from photoidentification data: confidence distributions and reduced likelihood for bowhead whales off Alaska.

Schweder, Tore (2001). Discrete distance sampling with difficulties.

Schweder, Tore (2001). Fishers paradigmerevolusjon, et 79års jubileum.

Schweder, Tore (2001). Minnetale over Olav Reiersøl.

Schweder, Tore (2001). Olav Reiersøl  statistiker, økonometriker og esperantist.
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Reiersøl var professor i matematisk statistikk fra 1961. Før det var han dosent og professor i matematikk, men hele tiden matematisk statistiker. Han døde i februar, nesten 93 år gammel. Reiersøls hovedfunn var at den enkleste konfluensanalysesmodellen til Frisch bare var uidentifiserbar når de latente variablene var normalfordelte. Hva betyr dette, hvorfor er det et viktig funn og hvordan kom Reiersøl til å interessere seg for dette spørsmålet? Hva ellers fant Reiersøl i sin forskning? Var han like en like original forsker som person, veileder og lærer?

Schweder, Tore (2001). Revolusjoner og kontrarevolusjoner i teoretisk statistikk  kan frekventistisk Bayesianisme bringe varig fred?.

Schweder, Tore (2001). Skepsisens plass i biologien  om falske funn og fordreid usikkerhet. Biolog.
ISSN 08010722.
19(3/4), s 6 12
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På bakgrunn av diskusjon om parapsykologi og om hval og hvalfangst innen IWC, settes sunn skepsis opp mot notorisk skepsis av kverulantisk art. Usunn og vedvarende skepsis kan undergrave forskningsprosessens integritet, og kan i ekstreme tilfeller regenes som uskikk i forskningen, på linje med fabrikasjon og falsifikasjon.

Schweder, Tore (2001). Statistical Methods, History of: Post1900, In Neil J. Smelser & Paul B Baltes (ed.),
International Encyclopedia of the Social & Behavioral Sciences.
Elsevier.
ISBN 0080430767.
s 15031
 15037

Schweder, Tore (2001). The NeymanPearson lemma for confidence distributions.

Schweder, Tore & Hjort, Nils Lid (2001). Confidence and Likelihood.

Hirst, David; Høst, Gudmund; Schweder, Tore; Fotland, Åge; Jakobsen, Tore; Skaug, Hans Julius; Mehl, Sigbjørn & Bogstad, Bjarte (2000). Towards a statistical model for the uncertainty in fisheries data for stock asssessment in the Barents Sea. NRnotat. SAMBA/06/00.

Schweder, Tore (2000). Bør høye kvoter kappes ned? Bioøkonomisk modellering og simulering av torskefisket.

Schweder, Tore (2000). Bør høye kvoter kappes ned? Bioøkonomisk modellering og simulering av torskefisket.
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Fisket reguleres nå stort sett på biologisk grunnlag. Kvotene varierer kraftig. Systemet i Barentshavet er modellert og simulering viser at lønnsomheten i fisket og samfunnets ressursrente bedres ved å kappe kvotene ned til et velvalgt øvre tak når de er høye. Overraskende nok blir ikke fangstene redusert i det lange løp ved fornuftig kvotekapping. En geometrisk versjon av den stokastiske OrnsteinUhlenbeck prosessen blir også diskutert i dette perspektivet.

Schweder, Tore (2000). Confidence distributions and likelihood.
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Confidence distributions are the frequentist's analogues of Bayesian priors and posteriors. Being a frequentist concept, the possible bias in a confidence distribution is well defined. Approximately unbiased posterior confidence distributions are obtained by bootstrapping of the likelihood based on the data and on possible prior confidence distributions based on previous data. As distinct from Bayesian analysis, information on the probability basis of a prior distribution is necessary to combine it with the data likelihood. Being a likelihood analysis, no problem arise if there are more or fewer prior distributions (with corresponding likelihood components) than there are free parameters in the model.

Schweder, Tore (2000). Confidence distributions and reduced likelihood.

Schweder, Tore (2000). Frequentist versions of posteriors and priors.
Show summary
Confidence distributions (Fisher's fiducial distributions) are the frequentist's analogues of Bayesian priors and posteriors. The quantiles of a confidence distribution are end points of confidence intervals for the parameter in question. To combine a prior confidence distribution with the likelihood of new data, it must be converted to a likelihood summarizing the past data. The two likelihood components are then multiplied together, and posterior confidence distributions are obtained for the parameters of interest. This frequentist approach is compared to the Bayesian approach with respect to bias and other issues.

Schweder, Tore (2000). Integrative fish stock assessment by frequentist methods: confidence distributions and likelihoods for bowhead whales.
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Frequentism in theoretical statistics evolved from R.A. Fisher's paradigmatic revolution in 1922, which partly was against the then prevailing Bayesianism. We now see a counterrevolution in fisheries and also elsewhere: back to Bayes. Is it necessary to depart from Fisher's methodology to use distributions as inputs and outputs of statistical analysis, and to integrate diverse data? Or can Fisher deliver the main attractions of Bayes, without some of the disturbing shortcomings? The frequentist methodology to be sketched is illustrated on data concerning bowhead whales. It involves the integration of diverse data, via the likelihood; the use of confidence distributions for inference about interest parameters; and obtaining confidence distributions and their accompanying reduced likelihoods through simulation experiments. A reduced likelihood summarizes the information in the data regarding a specific parameter, and might be used in later meta analyses. The approach might be attractive in the scientific context, where subjectivity should be kept to a minimum, where results should be unbiased and where the statistical uncertainty needs to be presented in the format of a distribution.

Schweder, Tore & Hjort, Nils Lid (1999). Frequentist analogues of priors and posteriors. Statistical research report (Universitetet i Oslo. Matematisk institut. 8.
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Published Oct. 1, 2010 2:10 PM
 Last modified Jan. 22, 2016 10:15 AM