Intraclass correlation (ICC) API

Computes intraclass correlation from a subjects x raters matrix, returning ICC(1,1), ICC(2,1), and ICC(3,1) from the one/two-way ANOVA mean squares, with a Koo-Li reliability verdict. Answers 'How consistent are my raters/measurements?', 'Which ICC form applies and what is its value?'.

Price$0.06per request

MethodPOST

Route/v1/stats/intraclass-correlation

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

psychometricsiccintraclass-correlationreliabilityratersanovaagreementmeasurement

API URLhttps://x402.hexl.dev/v1/stats/intraclass-correlation

Integration docs

Example request

{
  "matrix": [
    [
      9,
      2,
      5,
      8
    ],
    [
      6,
      1,
      3,
      2
    ],
    [
      8,
      4,
      6,
      8
    ],
    [
      7,
      1,
      2,
      6
    ],
    [
      10,
      5,
      6,
      9
    ],
    [
      6,
      2,
      4,
      7
    ]
  ]
}

Example response

{
  "icc1_1": 0.165742,
  "icc2_1": 0.289764,
  "icc3_1": 0.714841,
  "nSubjects": 6,
  "nRaters": 4,
  "meanSquares": {
    "MSB": 11.241667,
    "MSW": 6.263889,
    "MSC": 32.486111,
    "MSE": 1.019444
  },
  "interpretation": "ICC(2,1) indicates poor reliability"
}

Input schema

{
  "type": "object",
  "required": [
    "matrix"
  ],
  "properties": {
    "matrix": {
      "type": "array",
      "items": {
        "type": "array",
        "items": {
          "type": "number"
        }
      },
      "description": "subjects (rows) x raters (cols) score matrix",
      "examples": [
        [
          [
            9,
            2,
            5,
            8
          ],
          [
            6,
            1,
            3,
            2
          ]
        ]
      ]
    }
  }
}

Output schema

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