# Comparative Research Knowledge

## Comparative Research Principles

When comparing two or more subjects, align same indicators under same conditions.

| Criterion | Judgment |
|-----------|----------|
| Both subjects' data aligned on same indicator and year | OK |
| Only one side has data | REJECT |
| Indicator definitions differ between subjects | Warning (note the differences) |
| Comparing absolute values without considering scale | Warning (add per-capita ratios) |

### Aligning Comparison Axes

When subjects differ in scale or background, direct comparison can be misleading. Normalize (per capita, per area, etc.) and explicitly state condition differences.

## Comparative Data Collection

In comparative research, data for only one side halves the value.

| Criterion | Judgment |
|-----------|----------|
| Collected from the same data source for all subjects | OK |
| Collected from different data sources per subject | Warning (verify comparability) |
| Data missing for some subjects | Note gaps, limit comparison to available range |

### Determining Non-comparability

When indicator definitions fundamentally differ, report "not comparable" rather than forcing comparison. Identify partially comparable items and state the comparable scope.
