Suchergebnisse

The application of experimental & quasi-experimental methods to the study of environmental problems is recommended. Issues which must be taken into account in quasi-experimental studies are reviewed. Research possibilities in collective goods situations include investigation of demand for underpriced goods & of programs for changing usage of collective goods. Problems of causal analysis in time-series data reviews include determination of whether trends before & after a treatment fit the same or different patterns, & avoidance of spurious causal inferences. Outlined is a new causal interpretative procedure, the event-causing analysis, typical of historical analysis, which infers events from prior variables. Site selection procedures are problematic for both types of quasi-experimental research. New possible research techniques are discussed. 3 Figures. Modified HA.

There are several contexts in which randomization in research design is not possible. Researchers may be interested in the effects of large-scale events or policy initiatives, or of complex causal processes that cannot be replicated. Threats to external validity in randomized experiments will lead to greater dividends for some research questions in a quasi-experimental design. Quasi-experiments can offer opportunities for testing causal theories, if they are carefully constructed to counter threats to internal validity. Furthermore, randomization is not a simple guarantee against threats to internal validity where few units of observation are used. An appreciation of the intersection of these approaches-between stronger quasi-experiments and weaker randomized experiments-can help guide our choice of experimental method. One can make the same argument about the benefits of pursuing good opportunities with quasi-experiments over scant opportunities with randomized experiments as is made more often in reverse.

There are several contexts in which randomization in research design is not possible. Researchers may be interested in the effects of large-scale events or policy initiatives, or of complex causal processes that cannot be replicated. Threats to external validity in randomized experiments will lead to greater dividends for some research questions in a quasi-experimental design. Quasi-experiments can offer opportunities for testing causal theories, if they are carefully constructed to counter threats to internal validity. Furthermore, randomization is not a simple guarantee against threats to internal validity where few units of observation are used. An appreciation of the intersection of these approaches—between stronger quasi-experiments and weaker randomized experiments—can help guide our choice of experimental method. One can make the same argument about the benefits of pursuing good opportunities with quasi-experiments over scant opportunities with randomized experiments as is made more often in reverse.

AbstractSpecial problems arise when meta‐analysis is applied to quasi‐experiments. Careful consideration of threats to each study's validity may help the meta‐analyst to avoid these pitfalls.

Does the emigration of highly-skilled workers deplete local human capital? The answer is not obvious if migration prospects induce human capital formation. We analyse a unique natural quasi-experiment in the Republic of the Fiji Isalnds, where political shocks have provoked one of the largest recorded exoduses of skilled workers from a developing country. Mass emigration began unexpectedly and has occurred only in a well-defined subset of the population, creating a treatment group that foresaw likely emigration and two different quasi-control groups that did not. We use rich census and administrative microdata to address a range of concerns about experimental validity. This allows plausible causal attribution of post-shock changes in human capital accumulation to changes in emigration patterns. We show that high rates of emigration by tertiary-educated Fiji Islanders not only raised investment in tertiary education in Fiji; they moreover raised the stock of tertiary educated people in Fiji - net of departures.

Identifying the effect of parental incomes on child outcomes is difficult due to the correlation of unobserved ability, education levels and income. Previous research has relied on the use of instrumental variables to identify the effect of a change in household income on the young adult outcomes of the household´s children. In this research, we examine the role that an exogenous increase in household incomes due to a government transfer unrelated to household characteristics plays in the long run outcomes for children in affected households. We find that children who are in households affected by the cash transfer program have higher levels of education in their young adulthood and a lower incidence of criminality for minor offenses. These effects differ by initial household poverty status as is expected. Second, we explore two possible mechanisms through which this exogenous increase in household income affects the long run outcomes of children - parental time (quantity) and parental quality. Parental quality and child interactions show a marked improvement while changes in parental time with child does not appear to matter.

We examine the role that an exogenous increase in household income due to a government transfer unrelated to household characteristics plays in children's long run outcomes. Children in affected households have higher levels of education in their young adulthood and a lower incidence of criminality for minor offenses. Effects differ by initial household poverty status. An additional $4000 per year for the poorest households increases educational attainment by one year at age 21 and reduces having ever committed a minor crime by 22% at ages 16−17. Our evidence suggests that improved parental quality is a likely mechanism for the change.

All over the world, a very large number of elections take place concurrently with other elections for representatives in different government tiers. A crucial question for understanding electoral outcomes in those elections is the existence of electoral spillovers or coattail effects. Causal identification of coattail effects is challenging because popularity shocks typically affect parties in both concurrent elections. This paper exploits a quasi-experiment—the ban of a party in only one of the concurrent elections—to estimate coattail effects. The results show that a 1 pp decline in electoral support for a party in a given election reduces its support in the concurrent election by 0.25 pp. This comes along with a decline in turnout of the same size in both elections.

Abstract
The global energy mix and cost structure of the power industry are experiencing a redefinition. Many countries are revamping electricity-pricing systems to guarantee fixed-cost recovery, often by raising the fixed charge of two-part tariff schemes. However, a key assumption of two-part tariff schemes and associated fixed-cost recoveries is that consumers discriminate fixed from marginal costs. We conduct a quasi-experiment with data from a major electricity price reform recently implemented in Spain and find robust evidence indicating that consumers fail to distinguish between fixed and marginal costs. As a result, policymakers are not achieving the goal of cost recovery.

This study used a quasi-experimental design to assess the effectiveness of self-managing teams in a telecommunications company. These teams performed customer service, technical support, administrative support, and managerial functions in a variety of locations. The balance of evidence indicates that self-managing teams were more effective than comparable traditionally-managed groups that performed the same type of work. The study illustrates the value of a collaborative research project in which researchers and clients jointly define the research questions, study design, and methods.