(a) What is the dependent variable in each study? What is the independent variable? Hint: the independent variable is the feature that is manipulated in the study and the dependent variable is the feature you’re trying to study. For example, if I’m measuring the impact of images in solicitation letters on donations, the presence/absence of images is the independent variable and the giving is the dependent variable. See here for more examples:
(b) what is the sample size of each study? The sample size refers to the number of samples or observed instances in the study. To continue with my earlier example, if I send out 1,000 solicitation letters in my study, the sample size is 1,000.
(c) what was the conclusion of each study? In other words, what inferences did the researchers draw about the relationship between the independent and dependent variables? Again with the same example, if I find that the letters with images resulted in a 5% increase in average contribution amount, the conclusion would be that the presence of images is associated with an increase in contribution size.
(d) pick ONE of the studies and address, how strong is the evidence in favor of the conclusion? Consider the sample size, the effect size obtained, any caveats offered by the researchers, alternate explanations, etc.
In this course we will work on becoming better consumers of empirical
research–even if some of the statistical analyses may be unfamiliar we
can still begin to read these studies wisely. Thus it’s important to
begin working with some key concepts. Thus far I’ve assigned two
empirical studies: one by Kemp et al. and the other co-authored by Yale
professor Dean Karlan. Please address the following questions for these