# Effect sizes, confidence intervals and p-values

Decision workbook and teaching example · 2026-10-06

The completed case is fictional. Its values and decisions are not actual findings; complete your project using relevant permissions, methods and requirements.

- Project: ____________________
- Researcher and role: ____________________
- Date and version: ____________________
- Data seen before the decision: ____________________
- Aim and scope: ____________________

## Completed example

| Stage/decision | Example | Check or action |
| --- | --- | --- |
| Estimate | Hypothetical 2 points | Are units and direction clear? |
| CI95 | Illustrative [−1,5] | Are method and assumptions suitable? |
| Importance | 4 is only a teaching threshold | Was the actual threshold justified prospectively? |
| Interpretation | Uncertainty remains | Is p distinct from size and precision? |
| Report | Raw, standardized and limits | Is the standardizing denominator defined? |

## Complete your own record

| Topic | Actual decision and reason | Evidence link and status |
| --- | --- | --- |
| Estimate | __________ | __________ |
| CI95 | __________ | __________ |
| Importance | __________ | __________ |
| Interpretation | __________ | __________ |
| Report | __________ | __________ |

## Completion checks

- [ ] Write an estimate/interval/unit/importance-threshold table.

## Changes and limitations

| Date | Change | Data known at decision time | Reason | Consequence for claim | Reviewer |
| --- | --- | --- | --- | --- | --- |
| __________ | __________ | __________ | __________ | __________ | __________ |

## Sources and further reading

- [American Statistical Association — Statement on p-values](https://www.amstat.org/asa/files/pdfs/p-valuestatement.pdf)
- [UCLA Statistical Methods and Data Analytics — G*Power](https://stats.oarc.ucla.edu/other/gpower/)

Related guide: https://didgar-research-site1.vercel.app/en/guides/effect-size-uncertainty/