Orders and Observations Work Group | Maturity Level: 0 | Informative | Use Context: Any |

This is a value set defined by the FHIR project.

**Summary**

Defining URL: | http://hl7.org/fhir/ValueSet/observation-statistics |

Version: | 3.4.0 |

Name: | StatisticsCode |

Definition: | The statistical operation parameter -"statistic" codes. |

Committee: | Orders and Observations Work Group |

OID: | 2.16.840.1.113883.4.642.3.405 (for OID based terminology systems) |

Source Resource | XML / JSON |

This value set is used in the following places:

- This value set is the designated 'entire code system' value set for StatisticsCode

This value set includes codes from the following code systems:

- Include all codes defined in
`http://terminology.hl7.org/CodeSystem/observation-statistics`

This expansion generated 07 Aug 2018

This value set contains 21 concepts

Expansion based on http://terminology.hl7.org/CodeSystem/observation-statistics version 3.4.0

All codes from system `http://terminology.hl7.org/CodeSystem/observation-statistics`

Code | Display | Definition |

average | Average | The [mean](https://en.wikipedia.org/wiki/Arithmetic_mean) of N measurements over the stated period. |

maximum | Maximum | The [maximum](https://en.wikipedia.org/wiki/Maximal_element) value of N measurements over the stated period. |

minimum | Minimum | The [minimum](https://en.wikipedia.org/wiki/Minimal_element) value of N measurements over the stated period. |

count | Count | The [number] of valid measurements over the stated period that contributed to the other statistical outputs. |

total-count | Total Count | The total [number] of valid measurements over the stated period, including observations that were ignored because they did not contain valid result values. |

median | Median | The [median](https://en.wikipedia.org/wiki/Median) of N measurements over the stated period. |

std-dev | Standard Deviation | The [standard deviation](https://en.wikipedia.org/wiki/Standard_deviation) of N measurements over the stated period. |

sum | Sum | The [sum](https://en.wikipedia.org/wiki/Summation) of N measurements over the stated period. |

variance | Variance | The [variance](https://en.wikipedia.org/wiki/Variance) of N measurements over the stated period. |

20-percent | 20th Percentile | The 20th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period. |

80-percent | 80th Percentile | The 80th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period. |

4-lower | Lower Quartile | The lower [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period. |

4-upper | Upper Quartile | The upper [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period. |

4-dev | Quartile Deviation | 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. |

5-1 | 1st Quintile | 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. |

5-2 | 2nd Quintile | 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. |

5-3 | 3rd Quintile | 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. |

5-4 | 4th Quintile | 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. |

skew | Skew | 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). |

kurtosis | Kurtosis | 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). |

regression | Regression | 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. |

See the full registry of value sets defined as part of FHIR.

Explanation of the columns that may appear on this page:

Lvl | A few code lists that FHIR defines are hierarchical - each code is assigned a level. For value sets, levels are mostly used to organize codes for user convenience, but may follow code system hierarchy - see Code System for further information |

Source | The source of the definition of the code (when the value set draws in codes defined elsewhere) |

Code | The code (used as the code in the resource instance). If the code is in italics, this indicates that the code is not selectable ('Abstract') |

Display | The 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 |

Definition | An explanation of the meaning of the concept |

Comments | Additional notes about how to use the code |