Split-half + Spearman-Brown API

Correlates two half-test score arrays and applies the Spearman-Brown prophecy formula to estimate full-test reliability. Answers 'How reliable is my test from a single administration?', 'What does Spearman-Brown project for the whole test?'.

Price$0.04per request

MethodPOST

Route/v1/stats/split-half-reliability

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

psychometricsreliabilitysplit-halfspearman-brownprophecytest-theorysurveycorrelation

API URLhttps://x402.hexl.dev/v1/stats/split-half-reliability

Integration docs

Example request

{
  "half1": [
    5,
    4,
    3,
    6,
    7,
    5
  ],
  "half2": [
    4,
    5,
    3,
    5,
    8,
    4
  ]
}

Example response

{
  "halfHalfCorrelation": 0.821071,
  "spearmanBrownReliability": 0.901745,
  "nRespondents": 6,
  "interpretation": "excellent internal consistency (full-test, Spearman-Brown corrected)"
}

Input schema

{
  "type": "object",
  "required": [
    "half1",
    "half2"
  ],
  "properties": {
    "half1": {
      "type": "array",
      "items": {
        "type": "number"
      },
      "examples": [
        [
          5,
          4,
          3,
          6,
          7,
          5
        ]
      ]
    },
    "half2": {
      "type": "array",
      "items": {
        "type": "number"
      },
      "examples": [
        [
          4,
          5,
          3,
          5,
          8,
          4
        ]
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}