Description
When reverse is true return lower+upper-value, otherwise preserve value; reversed echoes the flag.
Numeric score transformations can reverse a scale, map anchors or change its mean and standard deviation. Such arithmetic does not establish equal category spacing, comparable constructs or statistical equating between assessments.
When reverse is true return lower+upper-value, otherwise preserve value; reversed echoes the flag.
When to use this tool
Use Scale Direction Reversal Flag when checking an explicit scale or anchor transformation.
How to use the tool and how it works
- Enter value, lower, upper, reverse. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read value, reversed. Inspect reversed before interpreting the associated values.
Require lower <= value <= upper. When reverse is true return lower+upper-value, otherwise preserve value; reversed echoes the flag.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| value | Value | Required. Finite number. |
| lower | Lower bound under the stated coordinate, derivative or uncertainty convention. | Required. Finite number. |
| upper | Upper bound under the stated coordinate, derivative or uncertainty convention. | Required. Finite number. |
| reverse | Reverse | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| value | Value | Required. Finite number. |
| reversed | Reversed | Required. Boolean. |
{
"input": {
"value": 2,
"lower": 0,
"upper": 5,
"reverse": true
},
"output": {
"value": 3,
"reversed": true
}
}Limitations and assumptions
- The reversal rule is supplied, not inferred from item wording. Numeric bounds do not establish that a scale is interval-valued or valid for the intended construct.
- 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 appropriate measurement validation or equating methods before treating transformed scales as interchangeable.
References
Similar or alternative tools
- Scale Reverse Item Midpoint
midpoint = lower/2+upper/2; reversed = lower+(upper-score).
- Teacher Rating Scale Width
width = upper-lower; intervals = width/step; aligned = Number.isInteger(intervals).