Seemingly similar individuals often experience drastically different success trajectories, with some repeatedly failing and others consistently succeeding. One explanation is preexisting variability along unobserved fitness dimensions that is revealed gradually through differential achievement. Alternatively, positive feedback operating on arbitrary initial advantages may increasingly set apart...

Experimental methods have been under criticism since the advent of mobile and ubiquitous technologies, due to clear limitations in their suitability for studies in the field. However, the laboratory paradigm cannot be directly transferred to field conditions because of its strict notions of experimentation. This chapter examines the theory of quasiexperimentation as an alternative conceptualiza...

W hen it comes to the role of theory in their research, empirical microeconomists are torn. On the one hand, we devote a large fraction of our graduate instruction to models of consumer behavior and fi rm decision making, and to the interactions that determine market equilibrium. On the other hand, it is not always obvious how these theories are relevant to empirical research. Outside the acade...

This paper discusses the experimental evaluation of locationbased services, such as mobile guides, in the field. It identifies advantages and disadvantages of using such field experiments over and against other evaluation methods. We then describe a specific method of running field experiments that we have found to be useful. The use of various evaluation measures, tools and scales is then disc...

parasitoids of the genus, trichogramma are the most widely used natural enemies for biological control of pests worldwide. the presence of flowering plants can improve efficiency of biological control agents by supplying sugar resource for parasitoids. in this study, two experiments were performed under laboratory condition (at 25±1ºc, 60±10% rh and a photoperiod 16l:8d), to evaluate the effect...

We report briefly on a set of online field experiments conducted as part of the CommunityLab collaborative research project. Based on these projects, and the published research literature, we present an analysis of the design choices for online field experiments and report on lessons learned.

The MHD mode trajectory in the Madison Symmetric Torus reversed-field pinch has been found to obey the sine-Gordon equation. Corresponding to experiment, a perturbation analysis predicts the locations of mode locking to be at the vacuum chamber poloidal and/or toroidal gaps. The mode's energy dissipates when it locks, as shown by a decaying spiral phase-plane trajectory. Unlocked modes travel a...

We conducted three field experiments to investigate how people schedule and complete tasks, providing some of the first data concerning procrastination and willpower under financial incentives. In our first study, we paid students $95 if they completed 75 hours of monitored studying over a five-week period. We also required people to meet interim weekly targets in one treatment, but not in the ...

Behala, a village about six miles from Calcutta, and have been treated in the Carmichael Hospital for Tropical Diseases. We have from time to time visited this settlement, as it was thought that a study of the conditions might throw some light on the transmission problem. Except that they are more sanitary, the general conditions under which these boys live are very similar to those prevailing ...

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