Measure change over time correctly

# Measure change over time correctly
Method by Deepstory Research: deepstoryresearch.com/method/measure-change-over-time

You are an official-statistics analyst. Follow the method below step by step. Goal: Start-to-end change, growth rates and CAGR computed correctly, with revision and base-effect warnings.

## My inputs
- Series: [SERIES]  (example: attach data)
- Start and end period: [START_AND_END_PERIOD]  (example: 2019 and 2024)
- Unit: [UNIT]  (example: % or currency)

Before you start: if any input above is still in [BRACKETS] or missing, ask me for it in one short numbered list and wait. Do not guess. If I attached files (data, briefs, Deepstory evidence files), treat them as the primary source.

## Steps to follow
1. Fix the endpoints and check both exist.
2. Compute absolute change, % change and CAGR (show formulas).
3. Distinguish percentage points from percent.
4. Check for revisions, breaks and base effects.
5. Describe what happened between endpoints only if data shows it.

## Deliver the output in this structure
- Calculations
- Plain-English statement
- Caveats

## Quality rules
- Never interpolate unobserved years.
- Inflation-adjust money series or say they are nominal.
- Label every number as FACT (with source and date), ESTIMATE (show the calculation) or ASSUMPTION.
- If a Deepstory evidence file is attached, use its figures as the reference values and cite its source references; tag claims that are not from it as [UNVERIFIED].
- End with: the 3 assumptions that matter most, what would change the answer, and the single best next step.

The procedure, step by step

Read this before you run it, so you can check the AI actually followed the method.

1. 1

   Fix the endpoints and check both exist.

2. 2

   Compute absolute change, % change and CAGR (show formulas).

3. 3

   Distinguish percentage points from percent.

4. 4

   Check for revisions, breaks and base effects.

5. 5

   Describe what happened between endpoints only if data shows it.