Sample Stratification
Stratify population items into caller-supplied value bands.
Description
Value stratification separates a population into caller-defined size bands.
Value stratification separates a population into caller-defined size bands.1
Stratify population items into caller-supplied value bands.
When to use Sample Stratification
Use this tool to stratify population items into caller-supplied value bands.
Prepare the documented facts, aligned totals or expected/observed evidence labels requested. Choose applicable requirements and thresholds separately before interpreting a planning screen.
How to use Sample Stratification and understand its results
- Prepare the documented facts, aligned totals or expected/observed evidence labels requested. Choose applicable requirements and thresholds separately before interpreting a planning screen.
- Enter itemValues, largeThreshold, mediumThreshold using the field table and calculation rules, then run the tool.
- Read largeCount, mediumCount, smallCount, largeValueSharePercent. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| itemValues | Population item values | list of number | Required |
| largeThreshold | Large-item threshold | number; minimum: 0 | Required |
| mediumThreshold | Medium-item threshold | number; minimum: 0 | Required |
Enter nonempty nonnegative values and ordered nonnegative thresholds. Return counts and large-value share; zero total gives zero share.
large≥largeLimit; medium≥mediumLimit and <largeLimit; small<mediumLimit Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| largeCount | Large item count | integer; minimum: 0 |
| mediumCount | Medium item count | integer; minimum: 0 |
| smallCount | Small item count | integer; minimum: 0 |
| largeValueSharePercent | Large-item value share (%) | number; minimum: 0; maximum: 100 |
{
"input": {
"itemValues": [
1000,
500,
100,
50
],
"largeThreshold": 800,
"mediumThreshold": 200
},
"output": {
"largeCount": 1,
"mediumCount": 1,
"smallCount": 2,
"largeValueSharePercent": 60.60606060606061
}
}Limitations and assumptions
No audit sample is selected and no risk or representativeness inference is made.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Sampling Coverage: Measure audit sample coverage by item count and value. For a complementary task, use Significant Transaction Class: Score a transaction class for audit significance.
References
-
Sample Stratification — tool.io
Similar or alternative tools
- Sampling Coverage
Measure audit sample coverage by item count and value.
- Significant Transaction Class
Score a transaction class for audit significance.