Crime Trend Percent Change YoY Calculator
Matched same-period year-on-year recorded-event change. Classification/coverage changes independently reconciled; zero prior count undefined, not crime incidence or causal policy effect.
Description
Year-on-year percent change compares recorded counts on a matched basis.
Year-on-year percent change compares recorded counts on a matched basis.1
A positive previous count is needed for a defined relative change. Use this tool to calculate the stated observation or conditional model from supplied measurements.
When to use Crime Trend Percent Change YoY Calculator
Use this tool to calculate the stated observation or conditional model from supplied measurements. Establish the jurisdiction or research scope, observation and event definitions, reference date, matched period and denominator basis.
How to use Crime Trend Percent Change YoY Calculator and understand its results
- Establish the jurisdiction or research scope, observation and event definitions, reference date, matched period and denominator basis.
- Enter previousMatchedRecordedCount, currentMatchedRecordedCount, using the field meanings and rules below, then run the tool.
- Read result.signedRecordedChangePercent. Interpret each field using the units, signs and evidence rules below.
- If input validation fails, correct the reported field and run again. Before applying a successful result, check the stated reference scope, units, assumptions and any retained unknown evidence.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| previousMatchedRecordedCount | Previous matched recorded count | number | Required |
| currentMatchedRecordedCount | Current matched recorded count | number | Required |
Require positive previous count and nonnegative current count on a matched basis. Return 100×(current−previous)/previous. Fractional quantities are accepted; previous zero fails instead of returning an invented percent change.
signedChangePercent=100×(current−previous)/previous Apply the field units and exact ordering, boundary and evidence rules above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Structured result containing the calculation or selected reference fields below | object |
| result.signedRecordedChangePercent | Signed Recorded Change Percent; use the units, sign convention and calculation stated above | number |
{
"input": {
"previousMatchedRecordedCount": 100,
"currentMatchedRecordedCount": 80
},
"output": {
"result": {
"signedRecordedChangePercent": -20
}
}
}Limitations and assumptions
A positive previous count is needed for a defined relative change. Results depend on the independently established measurement basis and the exact model assumptions above.
Every listed input requires an explicit value. Unexpected fields, incorrect value types, nonfinite numbers and sparse numeric arrays fail validation; tool-specific bounds and alignment rules apply as described above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful calculation that reports a false comparison or retains unknown evidence.
Alternative or Complementary methods
Use Unemployment Crime Correlation Calculator to examine a related aspect: Correlation describes linear association among matched region-period observations.
Use Lead Exposure Crime Lag Decades Reference Lookup where its separate inputs and scope apply: Lead-exposure and crime-lag studies compare populations under particular research designs.
References
Similar or alternative tools
- Unemployment Crime Correlation Calculator
Correlation describes linear association among matched region-period observations.
- Lead Exposure Crime Lag Decades Reference Lookup
Lead-exposure and crime-lag studies compare populations under particular research designs.