Linear-model residual pattern review ==================================== StatMedAnalysis | Original downloadable worksheet | 6 November 2026 Use residual diagnostics to investigate model specification rather than certify it. How to use this worksheet Record the fitted model and observation unit. Examine residuals against fitted values and important predictors, then inspect residual distribution and unusual observations. Consider dependence and measurement issues before choosing a remedy. Retain the original and revised model rationale. Save a working copy and keep the original blank version. Use public, hypothetical or aggregate information only; do not enter patient identifiers, credentials or confidential records. Keep source evidence in your approved project workspace. Mark unresolved text fields UNKNOWN or NOT REPORTED with a reason; never substitute zero for an unknown count. Project/version __________________ Prepared by role/date __________________ Working fields 1. Outcome and model equation Response/evidence: _________________________________________________________ ___________________________________________________________________________ 2. Residual type and software Response/evidence: _________________________________________________________ ___________________________________________________________________________ 3. Residual-versus-fitted pattern Response/evidence: _________________________________________________________ ___________________________________________________________________________ 4. Predictor-specific pattern Response/evidence: _________________________________________________________ ___________________________________________________________________________ 5. Tail behavior and unusual observations Response/evidence: _________________________________________________________ ___________________________________________________________________________ 6. Dependence or clustering concern Response/evidence: _________________________________________________________ ___________________________________________________________________________ 7. Proposed revision and scientific reason Response/evidence: _________________________________________________________ ___________________________________________________________________________ 8. Recheck and remaining limitations Response/evidence: _________________________________________________________ ___________________________________________________________________________ Hypothetical worked case A fictional residual plot curves upward at both low and high fitted values. Adding a scientifically justified nonlinear term may address the mean structure; a normality test alone would not explain the pattern. Decision rule and limitations Treat diagnostics as evidence for investigation. A visually quiet plot does not prove the model is correct, and changes should be checked for consequences to the estimand and interpretation. Decision _______________________ Remaining uncertainty ____________________ Next action ____________________ Owner / review date ______________________ Independent check and discrepancy resolution _______________________________ Official method or reporting reference checked 6 November 2026 https://www.statsmodels.org/stable/diagnostic.html This is an original planning aid, not an official checklist, validated instrument, clinical recommendation or certificate of expert approval. Apply the referenced guidance to the specific design and record any additional requirements.