Binomial proportion interval plan
Method review date: 2026-11-03

Instructions: Save a copy, complete blanks and record unresolved questions. Use fictional or aggregate values only; never patient identifiers. This planning aid does not certify an analysis.

DEFINE THE QUANTITY
Outcome/event definition: ____
Population and time window: ____
Observation unit: ____
Independent observations with a common probability plausible? ____
Clustering, weights, censoring or repeated observations requiring another method: ____

RECONCILE COUNTS
Event count x: ____
Eligible observed denominator n: ____
Missing/excluded observations and reasons: ____
Check integer counts and 0 <= x <= n; n>0.
Source table/query/version: ____

SPECIFY AND CHECK METHOD
Planned confidence level: ____
Method: ____ (linked tool: two-sided 95% Wilson, no continuity correction)
Observed p=x/n: ____
Wilson center=(p+z²/(2n))/(1+z²/n): ____
Half-width=z*sqrt(p(1-p)/n+z²/(4n²))/(1+z²/n): ____
Use z=1.95996398454 for 95%. Lower/upper: ____
Independent recomputation/software/version: ____

REPORT RESPONSIBLY
Numerator/denominator, proportion and interval: ____
Zero observed events do not establish zero population risk.
Sampling/measurement limitations and approximation limits: ____
Do not interpret a frequentist interval as a95% probability assigned to this fixed parameter.

Practical guide: https://www.statmedanalysis.com/blog/wilson-proportion-interval
Project/version: ____  Completed by role/date: ____