This is a fantastic and crucial first step in designing a replication study! The choice between exact and conceptual replication defines your goals, methodology, and the interpretation of your results.

Let's break down each type, when to choose it, and its pros and cons.

1. Exact (Direct) Replication

Definition: An exact replication aims to reproduce the original study as closely as possible, using the same methods, materials, population characteristics, and analytical approaches. The goal is to see if the original findings can be obtained again under virtually identical conditions.

When to Choose Exact Replication:

• To Verify a Surprising or Highly Impactful Finding: If the original result is counter-intuitive, contradicts existing theory, or has significant practical/policy implications, an exact replication is essential to confirm its robustness.


• To Address Suspicions of Type I Error (False Positive): If the original study had a small sample size, borderline p-values, or used questionable statistical practices, an exact replication (especially with a larger sample) is vital.


• To Establish the Reliability of a Novel Effect: For a new phenomenon or a first-of-its-kind study, an exact replication helps confirm that the effect is indeed observable under specific conditions.


• When the Original Study is Foundational: If the original study is a cornerstone of a research area, confirming its basic findings is critical for the integrity of subsequent work.


• To Confirm Methodology: If there's doubt about the specific experimental setup or measurement, an exact replication directly tests if those specific methods yield the reported effect.


• To Assess the Reproducibility Crisis: Many exact replications are driven by the broader scientific community's effort to gauge the reproducibility of published literature.

• Direct Test of Original Finding: Clearly indicates whether the original effect is robust under its initial conditions.


• High Internal Validity: If successful, it strongly supports the validity of the original specific finding. If unsuccessful, it raises serious questions about the original.


• Clear Interpretation: Success means the effect is likely real under those conditions. Failure strongly suggests the original finding might have been a false positive or highly context-dependent.


• Builds Confidence: Confirmed exact replications enhance trust in specific published results.


• Relatively Straightforward Design: Requires meticulous attention to detail but doesn't demand new theoretical development.

• Limited Generalizability: Doesn't tell you if the effect holds in different populations, settings, or with different operationalizations.


• Doesn't Advance Theory Significantly: While it confirms specific findings, it doesn't typically extend theoretical understanding beyond the original scope.


• "Original Error" Problem: If the original study had a subtle flaw (e.g., demand characteristics, experimenter bias) that was unknowingly replicated, the replication might confirm a flawed effect.


• Can Be Difficult/Impossible: Access to original materials, specific populations, or identical equipment might be challenging or impossible. Original researchers may not share everything.


• Less "Novel" for Publication: Often perceived as less groundbreaking than conceptual replications, though this is changing with the open science movement.

2. Conceptual Replication

Definition: A conceptual replication aims to test the same theoretical idea or hypothesis as the original study, but using different methods, operationalizations, populations, or contexts. The goal is to determine if the underlying theoretical effect is robust and generalizable across different instantiations.

When to Choose Conceptual Replication:

• To Test Generalizability: If the original finding is well-established, a conceptual replication assesses if the underlying phenomenon extends to new populations, settings, or variations of the independent/dependent variables.


• To Advance Theory: By showing that a theoretical principle holds true across different operationalizations, conceptual replications strengthen and refine theories.


• To Address Methodological Limitations of the Original: If the original study had specific limitations (e.g., reliance on self-report, a specific sample, a narrow experimental paradigm), a conceptual replication can test the same idea using improved or alternative methods.


• To Explore Boundary Conditions: You might design a conceptual replication to see when and where the effect holds, and equally important, when it doesn't. This helps delineate the scope of a theory.


• When an Exact Replication is Impractical/Impossible: If you can't access the original materials, population, or setting, a conceptual replication might be the only feasible way to explore the original idea.


• To Demonstrate Robustness of an Underlying Construct: Instead of a specific operationalization, a conceptual replication focuses on the broader construct.

• Tests Generalizability and Robustness: Provides stronger evidence for the underlying theoretical phenomenon across diverse contexts.


• Advances Theory: Helps refine, extend, or specify the boundary conditions of a theory.


• Addresses Methodological Nuances: Less susceptible to the specific methodological quirks or errors of the original study.


• More "Novel" for Publication: Often seen as contributing new insights and therefore potentially more publishable.


• More Flexible Design: Allows for creative solutions and adaptations.

• Difficult Interpretation of Failure: If a conceptual replication fails, it's harder to pinpoint why. Did the original theory fail, or did your new operationalization simply miss the mark, or was there an issue with your specific design?


• **Lower Internal Validity Check of Original Specific Finding:** It doesn't directly verify the original study's specific result under its original conditions.


• Requires More Design Expertise: Designing a conceptually equivalent but methodologically different study can be challenging.


• Risk of "Straw Man" Argument: If the conceptual replication diverges too much, critics might argue it's not truly replicating the original idea.


• Needs Careful Justification: You must clearly articulate why your new methods are conceptually equivalent to the original's.

Key Decision Factors for Your Study:

To help you decide, ask yourself the following questions:

• What is my primary goal?


• Is it to confirm a specific finding? (Exact)


• Is it to extend or generalize a theoretical idea? (Conceptual)


• Is it to check the validity of a novel or surprising finding? (Exact)


• Is it to improve upon the methodology of an existing finding? (Conceptual)


• How confident are we in the original finding?


• Is it a brand-new, never-before-seen effect? (Leans Exact first)


• Is it a well-established effect, but you want to see if it holds in a new context? (Leans Conceptual)


• Are there reasons to doubt the original's statistical power or methodology? (Leans Exact)


• What resources do I have?


• Can I access the original materials, code, and exact population? (Facilitates Exact)


• Do I have the expertise and time to design entirely new but theoretically equivalent methods? (Facilitates Conceptual)


• What is the impact of the original finding?


• Does it have policy implications? Is it highly controversial? (Strong argument for Exact)


• Is it a foundational piece of theory that needs broad empirical support? (Leans Conceptual, after initial exact verification if needed)

Recommendation: Often, a Hybrid Approach or Sequential Steps

It's common (and often ideal) to pursue both:

• Start with an Exact Replication: Especially for a novel or surprising finding. This establishes the basic phenomenon under its initial conditions.


• Follow with Conceptual Replications: Once the effect is confirmed to be robust under original conditions, then you can start varying aspects (population, context, operationalization) to test its generalizability and theoretical boundaries.

• Choose Exact if your priority is to verify the original specific result as a baseline, especially if you have doubts about its initial robustness or if it's a very new finding.


• Choose Conceptual if the original finding is reasonably well-established and your priority is to explore its broader theoretical implications, generalizability, or refine the underlying theory.

Good luck with your replication study design!