{

"resourceType": "CodeSystem",
"id": "observation-statistics",
"meta": {
  "lastUpdated": "2019-11-01T09:29:23.356+11:00"
},
"url": "http://terminology.hl7.org/CodeSystem/observation-statistics",
"identifier": [
  {
    "system": "urn:ietf:rfc:3986",
    "value": "urn:oid:2.16.840.1.113883.4.642.4.1126"
  }
],
"version": "4.0.1",
"name": "StatisticsCode",
"title": "StatisticsCode",
"status": "draft",
"experimental": false,
"date": "2019-11-01T09:29:23+11:00",
"publisher": "HL7 (FHIR Project)",
"contact": [
  {
    "telecom": [
      {
        "system": "url",
        "value": "http://hl7.org/fhir"
      },
      {
        "system": "email",
        "value": "fhir@lists.hl7.org"
      }
    ]
  }
],
"description": "The statistical operation parameter -\"statistic\" codes.",
"caseSensitive": true,
"valueSet": "http://hl7.org/fhir/ValueSet/observation-statistics",
"content": "complete",
"concept": [
  {
    "code": "average",
    "display": "Average",
    "definition": "The [mean](https://en.wikipedia.org/wiki/Arithmetic_mean) of N measurements over the stated period."
  },
  {
    "code": "maximum",
    "display": "Maximum",
    "definition": "The [maximum](https://en.wikipedia.org/wiki/Maximal_element) value of N measurements over the stated period."
  },
  {
    "code": "minimum",
    "display": "Minimum",
    "definition": "The [minimum](https://en.wikipedia.org/wiki/Minimal_element) value of N measurements over the stated period."
  },
  {
    "code": "count",
    "display": "Count",
    "definition": "The [number] of valid measurements over the stated period that contributed to the other statistical outputs."
  },
  {
    "code": "total-count",
    "display": "Total Count",
    "definition": "The total [number] of valid measurements over the stated period, including observations that were ignored because they did not contain valid result values."
  },
  {
    "code": "median",
    "display": "Median",
    "definition": "The [median](https://en.wikipedia.org/wiki/Median) of N measurements over the stated period."
  },
  {
    "code": "std-dev",
    "display": "Standard Deviation",
    "definition": "The [standard deviation](https://en.wikipedia.org/wiki/Standard_deviation) of N measurements over the stated period."
  },
  {
    "code": "sum",
    "display": "Sum",
    "definition": "The [sum](https://en.wikipedia.org/wiki/Summation) of N measurements over the stated period."
  },
  {
    "code": "variance",
    "display": "Variance",
    "definition": "The [variance](https://en.wikipedia.org/wiki/Variance) of N measurements over the stated period."
  },
  {
    "code": "20-percent",
    "display": "20th Percentile",
    "definition": "The 20th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period."
  },
  {
    "code": "80-percent",
    "display": "80th Percentile",
    "definition": "The 80th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period."
  },
  {
    "code": "4-lower",
    "display": "Lower Quartile",
    "definition": "The lower [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period."
  },
  {
    "code": "4-upper",
    "display": "Upper Quartile",
    "definition": "The upper [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period."
  },
  {
    "code": "4-dev",
    "display": "Quartile Deviation",
    "definition": "The difference between the upper and lower [Quartiles](https://en.wikipedia.org/wiki/Quartile) is called the Interquartile range. (IQR = Q3-Q1) Quartile deviation or Semi-interquartile range is one-half the difference between the first and the third quartiles."
  },
  {
    "code": "5-1",
    "display": "1st Quintile",
    "definition": "The lowest of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population."
  },
  {
    "code": "5-2",
    "display": "2nd Quintile",
    "definition": "The second of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population."
  },
  {
    "code": "5-3",
    "display": "3rd Quintile",
    "definition": "The third of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population."
  },
  {
    "code": "5-4",
    "display": "4th Quintile",
    "definition": "The fourth of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population."
  },
  {
    "code": "skew",
    "display": "Skew",
    "definition": "Skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean. The skewness value can be positive or negative, or even undefined.  Source: [Wikipedia](https://en.wikipedia.org/wiki/Skewness)."
  },
  {
    "code": "kurtosis",
    "display": "Kurtosis",
    "definition": "Kurtosis  is a measure of the \"tailedness\" of the probability distribution of a real-valued random variable.   Source: [Wikipedia](https://en.wikipedia.org/wiki/Kurtosis)."
  },
  {
    "code": "regression",
    "display": "Regression",
    "definition": "Linear regression is an approach for modeling two-dimensional sample points with one independent variable and one dependent variable (conventionally, the x and y coordinates in a Cartesian coordinate system) and finds a linear function (a non-vertical straight line) that, as accurately as possible, predicts the dependent variable values as a function of the independent variables. Source: [Wikipedia](https://en.wikipedia.org/wiki/Simple_linear_regression)  This Statistic code will return both a gradient and an intercept value."
  }
]

}