Release 5

This page is part of the FHIR Specification (v5.0.0: R5 - STU). This is the current published version in it's permanent home (it will always be available at this URL). For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4 R3

4.3.2.166 CodeSystem http://hl7.org/fhir/observation-statistics

Orders and Observations icon Work Group Maturity Level: 0Informative Use Context: Country: World
Official URL: http://hl7.org/fhir/observation-statistics Version: 5.0.0
active as of 2022-12-01 Computable Name: StatisticsCode
Flags: CaseSensitive, Complete. All codes ValueSet: Statistics Code OID: 2.16.840.1.113883.4.642.1.1126

This Code system is used in the following value sets:


The statistical operation parameter -"statistic" codes.

This code system http://hl7.org/fhir/observation-statistics defines the following codes:

CodeDisplayDefinitionCopy
average AverageThe [mean](https://en.wikipedia.org/wiki/Arithmetic_mean) of N measurements over the stated period.btn btn
maximum MaximumThe [maximum](https://en.wikipedia.org/wiki/Maximal_element) value of N measurements over the stated period.btn btn
minimum MinimumThe [minimum](https://en.wikipedia.org/wiki/Minimal_element) value of N measurements over the stated period.btn btn
count CountThe [number] of valid measurements over the stated period that contributed to the other statistical outputs.btn btn
total-count Total CountThe total [number] of valid measurements over the stated period, including observations that were ignored because they did not contain valid result values.btn btn
median MedianThe [median](https://en.wikipedia.org/wiki/Median) of N measurements over the stated period.btn btn
std-dev Standard DeviationThe [standard deviation](https://en.wikipedia.org/wiki/Standard_deviation) of N measurements over the stated period.btn btn
sum SumThe [sum](https://en.wikipedia.org/wiki/Summation) of N measurements over the stated period.btn btn
variance VarianceThe [variance](https://en.wikipedia.org/wiki/Variance) of N measurements over the stated period.btn btn
20-percent 20th PercentileThe 20th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period.btn btn
80-percent 80th PercentileThe 80th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period.btn btn
4-lower Lower QuartileThe lower [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period.btn btn
4-upper Upper QuartileThe upper [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period.btn btn
4-dev Quartile DeviationThe 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.btn btn
5-1 1st QuintileThe 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.btn btn
5-2 2nd QuintileThe 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.btn btn
5-3 3rd QuintileThe 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.btn btn
5-4 4th QuintileThe 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.btn btn
skew SkewSkewness 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).btn btn
kurtosis KurtosisKurtosis is a measure of the "tailedness" of the probability distribution of a real-valued random variable. Source: [Wikipedia](https://en.wikipedia.org/wiki/Kurtosis).btn btn
regression RegressionLinear 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.btn btn

 

See the full registry of code systems defined as part of FHIR.


Explanation of the columns that may appear on this page:

LevelA few code lists that FHIR defines are hierarchical - each code is assigned a level. See Code System for further information.
SourceThe source of the definition of the code (when the value set draws in codes defined elsewhere)
CodeThe code (used as the code in the resource instance). If the code is in italics, this indicates that the code is not selectable ('Abstract')
DisplayThe display (used in the display element of a Coding). If there is no display, implementers should not simply display the code, but map the concept into their application
DefinitionAn explanation of the meaning of the concept
CommentsAdditional notes about how to use the code