Vocabulary Work Group | Maturity Level: N/A | Standards Status: Informative |

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Definition for Code System StatisticsCode

{ "resourceType" : "CodeSystem", "id" : "observation-statistics", "meta" : { "lastUpdated" : "2019-04-18T15:23:58.606+00:00" }, "text" : { "status" : "generated", "div" : "<div>!-- Snipped for Brevity --></div>" }, "url" : "http://terminology.hl7.org/CodeSystem/observation-statistics", "identifier" : [{ "system" : "urn:ietf:rfc:3986", "value" : "urn:oid:2.16.840.1.113883.4.642.1.1126" }], "version" : "4.1.0", "name" : "StatisticsCode", "title" : "StatisticsCode", "status" : "draft", "experimental" : false, "date" : "2019-04-18T15:23:58+00:00", "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." }] }

Usage note: every effort has been made to ensure that the examples are correct and useful, but they are not a normative part of the specification.