Analysis invariance test plan
=============================

StatMedAnalysis | Original downloadable worksheet | 6 November 2026

Use known transformations to test calculations when a full reference answer is difficult.

How to use this worksheet
Identify mathematical properties that the statistic must satisfy under specified
transformations. State the conditions under which each property holds. Generate
synthetic transformed inputs and compare outputs. Include a deliberately invalid
transformation to ensure the property is not applied beyond its scope.

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. Statistic and implementation
Response/evidence: _________________________________________________________
___________________________________________________________________________

2. Transformation applied
Response/evidence: _________________________________________________________
___________________________________________________________________________

3. Expected invariant or changed result
Response/evidence: _________________________________________________________
___________________________________________________________________________

4. Conditions required
Response/evidence: _________________________________________________________
___________________________________________________________________________

5. Synthetic original input
Response/evidence: _________________________________________________________
___________________________________________________________________________

6. Transformed input and result
Response/evidence: _________________________________________________________
___________________________________________________________________________

7. Tolerance and failure evidence
Response/evidence: _________________________________________________________
___________________________________________________________________________

8. Scope limitations
Response/evidence: _________________________________________________________
___________________________________________________________________________

Hypothetical worked case
For a fictional arithmetic mean, adding 5 to every value should add 5 to the mean while
leaving the sample SD unchanged. Multiplying by a negative factor changes direction and
needs a separately stated rule.

Decision rule and limitations
Use invariance tests alongside reference cases and domain checks. A property can hold
even when other aspects of an implementation are wrong.

Decision _______________________  Remaining uncertainty ____________________
Next action ____________________  Owner / review date ______________________
Independent check and discrepancy resolution _______________________________

Official method or reporting reference checked 6 November 2026
https://docs.python.org/3/library/unittest.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.