scholarly journals Measurement uncertainty matters: ecological management using POMDPs

2016 ◽  
Author(s):  
Milad Memarzadeh ◽  
Carl Boettiger
Keyword(s):  
Measurement Error ◽  
Measurement Uncertainty ◽  
Complete Solution ◽  
Economic Returns ◽  
Classic Problem ◽  
Partially Observed ◽  
Markov Decision ◽  
The Impact ◽  
Stock Collapse

AbstractOver the past 30 years, researchers have used various approximations to address the impact of measurement uncertainty on optimal management policy.This literature has consistently suggested the counter-intuitive proposition that increasing harvest levels in the presence of measurement error is often optimal. Here, we use state-of-the art algorithms for Partially Observed Markov Decision Processes (POMDPs) to provide the first complete solution to this classic problem, and demonstrate that contrary to previous work, the resulting policy is usually more conservative than without measurement error. We demonstrate that management which underestimates the measurement error results in both low economic returns and high frequency of stock collapses, while overestimating the role of measurement error can still result in nearly-optimal economic performance while avoiding stock collapse.

scholarly journals Rebuilding global fisheries under uncertainty

2019 ◽  
Vol 116 (32) ◽  
pp. 15985-15990 ◽  
Author(s):  
Milad Memarzadeh ◽  
Gregory L. Britten ◽  
Boris Worm ◽  
Carl Boettiger
Keyword(s):  
Decision Making ◽  
Environmental Change ◽  
Measurement Uncertainty ◽  
Population Models ◽  
Decision Making Process ◽  
Future Prospects ◽  
Economic Returns ◽  
Stock Status ◽  
Decision Methods

Current and future prospects for successfully rebuilding global fisheries remain debated due to uncertain stock status, variable management success, and disruptive environmental change. While scientists routinely account for some of this uncertainty in population models, the mechanisms by which this translates into decision-making and policy are problematic and can lead to unintentional overexploitation. Here, we explicitly track the role of measurement uncertainty and environmental variation in the decision-making process for setting catch quotas. Analyzing 109 well-sampled stocks from all oceans, we show that current practices may attain 55% recovery on average, while richer decision methods borrowed from robotics yield 85% recovery of global stocks by midcentury, higher economic returns, and greater robustness to environmental surprises. These results challenge the consensus that global fisheries can be rebuilt by existing approaches alone, while also underscoring that rebuilding stocks may still be achieved by improved decision-making tools that optimally manage this uncertainty.

scholarly journals The Impact of Educational Mismatches on Wages: The Influence of Measurement Error and Unobserved Heterogeneity

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Sana Sellami ◽  
Dieter Verhaest ◽  
Walter Nonneman ◽  
Walter Van Trier
Keyword(s):  
Measurement Error ◽  
Unobserved Heterogeneity ◽  
Educational Background ◽  
Field Of Study ◽  
Wage Penalty ◽  
Random Measurement Error ◽  
Random Measurement ◽  
Worker Heterogeneity ◽  
The Impact

Abstract We investigate the differential impact of alternative combinations of horizontal and vertical educational mismatches on wages. By using panel data for Belgian graduates, we consider the role of unobserved worker heterogeneity. Random measurement error in both types of mismatches is accounted for by adopting instrumental variable techniques. We consistently find that overeducated individuals without field of study mismatch earn less than adequately educated workers with a similar educational background. However, for individuals who are working outside their field of study, such a wage penalty is not always observed once accounting for unobserved heterogeneity and random measurement error. In some cases, field of study mismatch even seems to be financially beneficial to the worker. These findings contribute to our understanding regarding the extent to which educational mismatches are truly problematic. The results call for policies that focus primarily on combatting vertical mismatches.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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