Description
Return two-wave score change and change per month.
Developmental research scores can be expressed as changes, ratios, reversed scales or contrasts between conditions. Those arithmetic forms have distinct denominators and need a suitable measurement model before they support psychological interpretation.
Return two-wave score change and change per month.
When to use this tool
Use Developmental Trajectory One Wave Change when checking a supplied score or response contrast.
How to use the tool and how it works
- Enter firstScore, secondScore, firstAgeMonths, secondAgeMonths. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read change, changePerMonth. Use the output convention below.
Return two-wave score change and change per month. Require nonnegative firstAgeMonths and strictly later secondAgeMonths; change = secondScore-firstScore and rate divides by elapsed months.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| firstScore | First Score | Required. Finite number. |
| secondScore | Second Score | Required. Finite number. |
| firstAgeMonths | First Age Months | Required. Finite number; minimum 0. |
| secondAgeMonths | Second Age Months | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| change | Change | Required. Finite number. |
| changePerMonth | Change Per Month | Required. Finite number. |
{
"input": {
"firstScore": 20,
"secondScore": 26,
"firstAgeMonths": 12,
"secondAgeMonths": 18
},
"output": {
"change": 6,
"changePerMonth": 1
}
}Limitations and assumptions
- Scores need a compatible scale; this does not fit a developmental trajectory or infer causality.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use validated instruments, an appropriate study design and professional assessment when interpreting individual development or cognitive function.
References
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