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Term of the Month

Defining Criminal Justice Research

Welcome to NIJ’s Term of the Month. Each month we are featuring a term from our scientific research portfolios informing significant American justice system issues and solutions.

February 2023 - Replication Research

A replication study is a scientific study that attempts to validate findings from prior research by asking the same or similar scientific questions as the original research study. Replication matters because the peer review process alone does not guarantee the integrity of the reported results. Replication studies strengthen science by independently confirming the validity of research findings. When results are consistent across studies, the results of the original study are more likely to reliable.  

Research is generalizable if a second study addresses a similar scientific question and finds consistent results in contexts or populations that differ from the original context or populations.

Not all scientific studies can be replicated. Non-replicability can be the result of uncertainty, or study limitations, such as:

  • Publication bias
  • Misaligned incentives
  • Inappropriate statistical inference
  • Poor study design
  • Researcher errors
  • Incomplete reporting of a study

In the social sciences, economics, clinical studies, and other fields, replication studies often include new data collections to verify original findings. A different term, reproducibility, measures whether a second study using the same data and the same or similar procedures as the original research yields consistent results.

The National Institute of Justice requires all research grantees to deposit data collected during the life of an award with the National Archive of Criminal Justice Data, an archive of datasets maintained for secondary analysis, to allow for replication studies.

NIJ research grant solicitations regularly encourage grant proposals for replication research.

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Date Created: January 28, 2021