AI Power-Analysis Narrative: Drafting Sample-Size Justification Sections
AI can draft power-analysis sample-size justification narratives, but the effect-size assumption stays with the investigator.
11 min · Reviewed 2026
The premise
AI can draft power-analysis narratives that document effect-size assumption, alpha, power, and the resulting sample-size estimate.
What AI does well here
Render the power-analysis assumption set into one paragraph.
Mirror the sensitivity-analysis approach across plausible effect sizes.
What AI cannot do
Decide the effect-size assumption.
Replace the biostatistician's calculation.
End-of-lesson check
15 questions · take it digitally for instant feedback at tendril.neural-forge.io/learn/quiz/end-research-ai-and-power-analysis-narrative-r7a3-creators
In drafting a power-analysis narrative for a two-arm RCT, which task can AI reliably perform?
Performing the statistical calculations that determine sample size
Selecting the primary outcome variable for the study
Converting a set of power-analysis assumptions into a coherent paragraph
Deciding which effect size the study should target
A researcher is planning a two-arm RCT with a continuous primary outcome. What is the single most consequential driver of the required sample size?
The number of participating research sites
The assumed effect size for the primary outcome
The duration of the follow-up period
The choice of statistical software
Why cannot AI independently determine the effect-size assumption for a study?
Power analysis software already contains the correct effect-size values
Effect-size assumptions require approval from the funding agency
The effect size must reflect clinically meaningful differences that only investigators can define
AI lacks access to the raw data needed for effect-size estimation
What does the lesson identify as a key capability of AI in power-analysis narrative drafting?
Selecting appropriate statistical tests for the primary outcome
Determining whether the study design is feasible
Mirroring the sensitivity-analysis approach across multiple plausible effect sizes
Calculating the exact sample size needed without any investigator input
In a power-analysis narrative for a two-arm RCT, which of the following elements must the investigator provide to AI before drafting can begin?
A list of all potential confounders
The statistical code in R or Python
The effect-size assumption, alpha level, and desired power
The complete raw dataset for analysis
A researcher asks an AI to determine the sample size for their two-arm RCT. What is the most accurate description of what AI can actually produce?
A decision on whether the study is ethically sound
A narrative justifying the sample size based on assumptions the researcher provides
A completed manuscript ready for submission
The final sample-size number without any justification text
What is sensitivity analysis in the context of power analysis for an RCT?
Calculating sample-size requirements across a range of plausible effect sizes
Testing how the study performs with different random assignment methods
Comparing results from multiple statistical software packages
Estimating the impact of different attrition patterns after data collection
A student claims that AI can replace the need for a biostatistician in designing an RCT. What is the correct counterargument?
AI cannot decide the effect-size assumption, which is fundamental to the calculation
AI cannot generate random allocation sequences
AI cannot perform interim analyses during the trial
AI cannot recruit participants into the study
When AI drafts a power-analysis narrative for a two-arm RCT, what happens to the ownership of the effect-size assumption?
It remains with the research team who must justify their choice
It automatically becomes standard practice in the field
It is assumed to be the largest effect size possible
It transfers to the AI system that generated the text
What does the lesson mean when it says the effect-size assumption 'drives the whole study'?
It determines whether the IRB will approve the protocol
It determines the required sample size, which affects feasibility, budget, and timeline
It determines which participants will be eligible for enrollment
It determines which journal will ultimately publish the results
A researcher wants AI to draft a power-analysis narrative but has not decided on an effect-size assumption. What should the researcher do first?
Use the largest effect size observed in prior pilot studies
Set the effect size to 0.5 by convention
Ask AI to suggest several effect sizes to choose from
Determine the smallest clinically meaningful difference they want to detect
A learner says, 'Since AI can write the power-analysis paragraph, I don't need to understand power analysis concepts.' What is the flaw in this reasoning?
Power analysis is no longer required by ethics committees
AI can independently verify that the study design is ethical
AI always produces accurate statistical calculations
The learner must still provide the correct inputs (effect size, alpha, power) for AI to work with
Why might a researcher include multiple effect sizes in their power-analysis narrative rather than a single value?
To confuse reviewers and demonstrate complexity
To meet regulatory requirements for all possible effect sizes
To show how sample-size needs change under different assumptions and to inform interpretation
To ensure the study will definitely be adequately powered
What information must be documented in a complete power-analysis justification for a two-arm RCT?
The sample size and the funding amount
Effect-size assumption, alpha, power, attrition rate, and resulting sample size
Only the sample size and the statistical test used
The effect size and the number of co-investigators
A researcher provides the following to AI: effect size of 0.3, alpha of 0.05, power of 0.80, and attrition of 10%. What can AI now produce?
A decision about whether to proceed with the study
A completed dataset for the RCT
A final analysis of the study results
A narrative paragraph documenting these assumptions and the resulting sample-size estimate