Browsing by Subject "field experiments"

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  • Verheijen, Frank G. A.; Mankasingh, Utra; Penizek, Vit; Panzacchi, Pietro; Glaser, Bruno; Jeffery, Simon; Bastos, Ana Catarina; Tammeorg, Priit; Kern, Juergen; Zavalloni, Costanza; Zanchettin, Giulia; Sakrabani, Ruben (2017)
    A representativeness survey of existing European Biochar field experiments within the Biochar COST Action TD1107 was conducted to gather key information for setting up future experiments and collaborations, and to minimise duplication of efforts amongst European researchers. Woody feedstock biochar, applied without organic or inorganic fertiliser appears over-represented compared to other categories, especially considering the availability of crop residues, manures, and other organic waste streams and the efforts towards achieving a zero waste economy. Fertile arable soils were also over-represented while shallow unfertile soils were under-represented. Many of the latter are likely in agroforestry or forest plantation land use. The most studied theme was crop production. However, other themes that can provide evidence of mechanisms, as well as potential undesired side-effects, were relatively well represented. Biochar use for soil contamination remediation was the least represented theme; further work is needed to identify which specific contaminants, or mixtures of contaminants, have the potential for remediation by different biochars.
  • Blanco Sequeiros, Sofia (Helsingin yliopisto, 2019)
    This thesis explores the problem of extrapolating causal claims in the social sciences, particularly economics. The problem of extrapolation is the problem of inferring something about a phenomenon of interest in one context, based on what is known about it in another. For example, we may want to infer that a medicine works in population $Y$, based on the fact that we know it works in population $X$. Extrapolation is the inferential process of generalizing or transporting claims about a phenomenon of interest to new populations or settings. The answers to the problem of extrapolation in philosophy of science aim to explain how successful extrapolation is possible, as there will always be relevant differences between the two systems. I study extrapolation from the viewpoint of philosophy of science, which aims to both analyze and complement science and scientific knowledge. I also use a case study with two examples to further illustrate the relationship between the theoretical approaches to extrapolation in philosophy of economics and actual studies in experimental economics. I focus on comparative process tracing, a general account of extrapolation developed by philosopher of science Daniel Steel, and its success in extrapolating causal claims from field experiments in economics. The first chapter introduces central concepts and key questions. The second chapter discusses external validity, a concept typically used in economics to describe the potential of causal claims to be extrapolated. The third chapter introduces comparative process tracing, which explains how and why extrapolation can be based on knowledge about causal mechanisms. Next, I discuss field experiments in economics and methodological issues of extrapolation particular to them. The fourth chapter consists of a case study, which shows the limitations of approaching extrapolation in economics with comparative process tracing. The last chapter concludes. The central conclusion of this thesis is that even though comparative process tracing is meant as an account of extrapolation that can explain and apply to extrapolation across disciplines, applying it to economics faces methodological challenges. Nevertheless, the issues it faces with regard to field experiments in economics do not refute it as an account of mechanistic extrapolation. I propose that comparative process tracing is a theoretically comprehensive epistemological account of extrapolation in the social sciences, but it must be complemented with a systematic methodological account of problems of extrapolation in practice. This methodological account complements and enhances epistemological analysis of extrapolation.
  • Nagatsu, Michiru; Favereau, Judith (2020)
    While the history and methodology of laboratory experiments in economics have been extensively studied by philosophers, those of field experiments have not attracted much attention until recently. What is the historical context in which field experiments have been advocated? And what are the methodological rationales for conducting experiments in the field as opposed to in the lab? This article addresses these questions by combining historical and methodological perspectives. In terms of history, we show that the movement toward field experiments in economics has two distinct roots. One is the general orientation of medical and social sciences to evidence-based policy evaluation, which gave rise to randomized field experiments in economics (e.g., behavioral public policy, poverty alleviation policy). The other is an awareness of several methodological limitations of lab experiments in economics, which required practitioners to get out of the lab and into the field. In these senses, the movement is a consequence of influences from both outside and inside economics: the general evidencebased trend in policy science and an internal methodological development of experimental economics. In terms of methodology, we show that these two roots resulted in two somewhat different notions of “external validity” as methodological rationales of field experiment. Finally, we suggest that analysis of experiments as exhibits highlights a methodological strategy in which both strands complement each other.