Tuesday, January 8, 2013

Opening the Floodgates?

Well, here it is, our call for proposals regarding pre-registered replication studies on cognition. When I say “our” I hasten to add that we stole and adapted the text of this call, with their permission, from Brian Nosek and Daniël Lakens who are guest editing a special issue of Social Psychology. Their original text is a great model for how replication studies should be solicited. It might become a standard feature of many journals in the years to come.
Our special issue will be an interesting experiment, the results of which we are awaiting with some trepidation. How many submissions can we expect? No idea. Are we opening the floodgates or will it be a slow trickle? Only time will tell. We take courage in our Dutch heritage (and I don’t mean Dutch courage). Taming the waters is in our blood.

Call for Proposals
Special Issue of Frontiers in Cognition
“Replications of Important Results in Cognition”
Guest Editors: René Zeelenberg & Rolf A. Zwaan

A signature strength of science is that the evidence is reproducible.  However, direct replications rarely appear in psychology journals because standard incentives emphasize novelty over verification (for background see Nosek, Spies, & Motyl, 2012, Perspectives on Psychological Science). This special issue, “Replications of Important Results in Cognition,” alters those incentives.  We invite proposals for high-powered, direct replications of important results in all areas of cognitive psychology, ranging from perception to social cognition. The review process will focus on the soundness of the design and analysis, not whether the outcome is positive or negative. 

What are important results?
Importance is subjective but demonstrable.  Proposals must justify the replication value of the finding to be replicated. To merit publication in this issue, the original result should be important (e.g., highly cited, a topic of intense scholarly or public interest, a challenge to established theories), but also should have uncertain truth-value (e.g., few confirmations, imprecise estimates of effect sizes). The prestige of the original publishing journal is not sufficient to justify replication value. 

What replication formats are encouraged?
Proposals should be for direct replications that faithfully reproduce the original procedure, materials, and analysis for verification. Conceptual replications that attempt to improve theoretical understanding by changing the operational definition of the constructs will not be considered for this issue. Articles in the issue can take two forms:

(1) Registered replication.  Authors submit the introduction, methods, and analysis plan for a replication study or studies. These proposals will be reviewed for their importance and soundness. Once provisionally accepted, if authors complete the study as proposed, the results will be published without regard to the outcome. Registered replication proposals also could include: (a) collaborations between two or more laboratories independently attempting to replicate an effect with the same materials, (b) joint replication by the original laboratory and another laboratory, or (c) adversarial collaborations in which laboratories with competing expectations prepare a joint registered proposal and conduct independent replications. Only adequately powered tests of results with high replication value will be considered.

(2) Registered replication + existing replication attempts.  Researchers may already have performed several experiments attempting to replicate published findings. These experiments may be included in the submission, but each submission should include at least one registered replication. Authors should report the experiments they have already completed (including the results) and describe the registered experiment that they plan to run.

How do I propose a replication project?
Interested authors should contact the guest editors before preparing a formal proposal (Rolf Zwaan, zwaan@fsw.eur.nl; René Zeelenberg, zeelenberg@fsw.eur.nl). These pre-proposal discussions will occur in early 2013, with the special issue scheduled for publication in 2014. Deadlines for the formal proposal and final manuscript depend on the type of project.  Registered replication proposals should be submitted by April 1, 2013 to leave time for initial review, revision, provisional acceptance, data collection, manuscript preparation, final review, and acceptance of the final report.

Registered Replications

Replication teams submit a replication proposal for review prior to initiating data collection.  Peer review includes an author of the original study and other relevant experts.  Review addresses two questions: (1) Does the finding have high replication value?, and (2) Is the proposed design a fair replication?  If accepted, the proposal is registered at the Open Science Framework (http://openscienceframework.org/) or equivalent registration site, and then data collection may commence.[1]  Proposals are accepted for publication conditional on following through with a competent execution of the proposed design.

Registered Replication Proposal
Replication proposals include a short introduction that describes the to-be-replicated finding, summarizes the existing evidence about the finding, and articulates why the finding has high replication value.  If the authors have already performed one or more replication attempts and wish to include those in their final paper these experiments and the results should be described in the proposal. The methods section is the central part of the replication proposal.  Because data collection for the registered experiment cannot start before the paper is provisionally accepted there are no results or discussion sections for registered experiments in the proposal.  The following should be included in the methods section:

1. Sampling plan.  Power analysis based on effect size of the existing evidence for the finding; planned sample size, manner of recruitment, and anticipated sample characteristics.  Ideally, studies will achieve .95 power to have equal likelihood of erroneously rejecting and accepting the null hypothesis.  When such power is not feasible, provide justification. 

2. Materials and procedure.  Ideally, authors obtain the original study materials to maximize comparability of the replication attempt. If not feasible or desirable, explain why.  Procedures are described as completely as possible so that reviewers can identify potential design improvements.  Additional material - such as videos simulating experimental conditions - can be made available to enhance transparency and review.

3. Known differences from original study.  No replication is exact.  Fair replications reproduce the features considered critical for obtaining the result.  Authors describe known differences and explain why these are not critical for a fair replication of the original finding. In general, authors should avoid making “improvements” on research designs unless a reasonable expert would agree that the changes improve the sensitivity of the design to detect the effect.

4. Confirmatory analysis plan.  The ideal analysis plan includes an executable script that would process the data and produce the confirmatory results.  At minimum, authors should describe the data cleaning plan - i.e., exclusion criteria for participants and observations; and the analysis process for evaluating the replication attempt. It should also describe the basis for evaluating the success of the replication.

Registering the Replication Project
Accepted proposals, and all shareable materials, are registered and made available publicly through the Open Science Framework (http://openscienceframework.org/) or equivalent registration venue.

Other research teams, including the original study authors, will have the opportunity to submit proposals to conduct a parallel replication following the registered project protocol.  Interested teams should email one of the editors of the special issue for information on applying. If accepted, these parallel replications will be very short independent papers that follow the “primary” report quickly summarizing design alterations, confirmatory results, and a brief conclusion.

Final Reports
After data collection and analysis.  Authors add a results section, discussion section, and an abstract.  The results section separated into two parts: confirmatory analysis and exploratory analysis.  The confirmatory analysis section reports the outcome of the registered analysis plan.  Authors may add exploratory analyses to further examine the finding.  Exploratory analyses should not address questions orthogonal to verification of the target of replication.  The discussion question summarizes the findings, draws conclusions about the results, and identifies limitations of the research.  Authors are encouraged to report a meta-analytic estimate and confidence interval for the study combined with the original study and any other replications. 

After acceptance of the final report, and any other parallel replications, the original study authors may be invited to write a brief commentary.  The commentary could also include reporting of a parallel replication attempt. 

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