In the interest of promoting open and reproducible science, the Journal of Experimental Political Science editorial team will pilot the pre-acceptance of preregistered reports. We note that the launch of this new submission option is a complement to, and does not replace, the option to submit other types of manuscripts. JEPS remains open to receiving and reviewing high quality manuscripts regardless of whether they are based on preregistered studies.

We are excited and honored to be the editorial team for JEPS. We are indebted to Eric Dickson for his efforts as the journal's previous editor. He set a high bar for JEPS as an outlet for high quality experimental research. Lucky for us, the healthy state of experimental research means that we will continue to have a deep pool of well-crafted and important work. We also thank Nick Haas, who deftly guided us through the transition as Editorial Assistant. Without his help, it would have been a near impossible task to get up to speed.

Political knowledge is a central concept in the study of public opinion and political behavior. Yet what the field collectively believes about this construct is based on dozens of studies using different indicators of knowledge. We identify two theoretically relevant dimensions: a temporal dimension that corresponds to the time when a fact was established and a topical dimension that relates to whether the fact is policy-specific or general. The resulting typology yields four types of knowledge questions. In an analysis of more than 300 knowledge items from late in the first decade of the 2000s, we examine whether classic findings regarding the predictors of knowledge withstand differences across types of questions. In the case of education and the mass media, the mechanisms for becoming informed operate differently across question types. However, differences in the levels of knowledge between men and women are robust, reinforcing the importance of including gender-relevant items in knowledge batteries.

Increasingly, experimental research is being conducted on the Internet in addition to the laboratory. Online experiments are more convenient for subjects and researchers, but we know little about how the choice of study location affects data quality. To investigate whether respondent behavior differs across study location, we randomly assign subjects to participate in a study in a laboratory or in an online setting. Contrary to our expectations, we find few differences between participants in terms of the level of attention and socially desirable responding. However, we find significant differences in two areas: the degree of self-reported distractions while completing the questionnaire and the tendency to consult outside sources for answers to political knowledge questions. We conclude that when the greater convenience (and higher response rates) of online experiments outweighs these disadvantages, Internet administration of randomized experiments represent an alternative to laboratory administration.

Researchers use survey experiments to establish causal effects in descriptively representative samples, but concerns remain regarding the strength of the stimuli and the lack of realism in experimental settings. We explore these issues by comparing three national survey experiments on Medicare and immigration with contemporaneous natural experiments on the same topics. The survey experiments reveal that providing information increases political knowledge and alters attitudes. In contrast, two real-world government announcements had no discernable effects, except among people who were exposed to the same facts publicized in the mass media. Even among this exposed subsample, treatment effects were smaller and sometimes pointed in the opposite direction. Methodologically, our results suggest the need for caution when extrapolating from survey experiments. Substantively, we find that many citizens are able to recall factual information appearing in the news but may not adjust their beliefs and opinions in response to this information.

How do traditional redistricting principles—contiguity, communities of interest, political subdivisions, incumbent protection, Section 5 of the Voting Rights Act, preservation of district core, and compactness—affect racial minority representation in congressional districts? Using data from the 2001-02 redistricting process, we find that compactness is the only principle that significantly affects minority representation, both in terms of majority-minority districts and minority influence districts, but these effects are contingent on the size of the minority community and extent of racial segregation in a state. Two other principles, Section 5 pre-clearance and protecting political subdivisions, improve minority representation in a more limited way. Thus, race-neutral redistricting criteria like the compactness principle, can dramatically affect the racial composition of the resulting districts and, thereby, affect minority representation.