DDI Controlled Vocabulary for Summary Statistic Type

Code List
Value of the Code	Descriptive Term of the Code	Definition of the Code
ArithmeticMean	Arithmetic mean (X)	Mathematical average of a set of values. The mean is calculated by adding up two or more values and dividing the total by their number. In social/political science, it is usually the sum of the measurements divided by the number of subjects, or cases.
GeometricMean	Geometric mean	Average value of all data if extracting the nth root of the product of all (n) values. Rarely used in social sciences.
HarmonicMean	Harmonic mean	Average value of all data if calculating the reciprocal of the arithmetic mean of the reciprocal of values. Rarely used in social sciences.
TrimmedMean	Trimmed mean	The (arithmetic) mean calculated after discarding given parts of observations at the high and low end (e.g., interquartile mean when the lowest 25% and the highest 25% are discarded, and the mean of the remaining values is calculated).
StandardErrorOfMean	Standard error of the mean	The Standard Error for the mean value.
Mode	Mode (Mo)	The most frequently observed data value (Statistics Canada).
Median	Median (Mdn)	The values below which, and above which, half of the values in a distribution fall (50th percentile).
ValidCases	Valid Cases	Cases with observations which are considered to be valid, i.e., providing substantial information and to be included for calculation.
InvalidCases	Invalid cases	Cases which are considered/defined as "missing" (e.g., not ascertained, not applicable, etc.), usually excluded from calculation.
Minimum	Minimum	The lowest valid value in a variable.
Maximum	Maximum	The highest valid value in a variable.
Range	Range	The range of valid values, i.e., all values that fall between the lowest and highest valid values.
Sum	Sum	The sum or total of the values, across all valid cases.
Variance	Variance (s2)	The variance is the mean square deviation of the variable around the average value. It reflects the dispersion of a frequency distribution around its mean (OECD Glossary of Statistics).
StandardDeviation	Standard deviation (s)	The positive square root of the variance. The most widely used measure of dispersion of a frequency distribution.
CoefficientOfVariation	Coefficient of variation (CV)	Standard deviation divided by the mean.
AverageAbsoluteDeviation	Average absolute deviation (AAD)	The average of the absolute differences between each value and the overall mean. Measure of statistical dispersion around the mean, alternative to Standard Deviation.
MedianAbsoluteDeviation	Median absolute deviation (MAD)	The median absolute deviation from the median. Measure of statistical dispersion around the median.
FirstQuartile	First quartile	The first of three values which separate the total frequency of a distribution into four equal parts.
Second Quartile	Second quartile	The second of three values which separate the total frequency of a distribution into four equal parts (= median).
ThirdQuartile	Third quartile	The third of three values which separate the total frequency of a distribution into four equal parts.
InterquartileRange	Interquartile range	The range between the first and third quartile values.
FirstQuintile	First quintile	The first of four values which separate the total frequency of a distribution into five equal parts.
SecondQuintile	Second quintile	The second of four values which separate the total frequency of a distribution into five equal parts.
ThirdQuintile	Third quintile	The third of four values which separate the total frequency of a distribution into five equal parts.
FourthQuintile	Fourth quintile	The fourth of four values which separate the total frequency of a distribution into five equal parts.
InterquintileRange	Interquintile range	The range between the first and fourth quintile values.
FirstDecile	First decile	The first of nine values which separate the total frequency of a distribution into ten equal parts.
SecondDecile	Second decile	The second of nine values which separate the total frequency of a distribution into ten equal parts.
ThirdDecile	Third decile	The third of nine values which separate the total frequency of a distribution into ten equal parts.
FourthDecile	Fourth decile	The fourth of nine values which separate the total frequency of a distribution into ten equal parts.
FifthDecile	Fifth decile	The fifth of nine values which separate the total frequency of a distribution into ten equal parts (= median).
SixthDecile	Sixth decile	The sixth of nine values which separate the total frequency of a distribution into ten equal parts.
SeventhDecile	Seventh decile	The seventh of nine values which separate the total frequency of a distribution into ten equal parts.
EighthDecile	Eighth decile	The eighth of nine values which separate the total frequency of a distribution into ten equal parts.
NinthDecile	Ninth decile	The ninth of nine values which separate the total frequency of a distribution into ten equal parts.
InterdecileRange	Interdecile range	The range between the first and ninth decile values.
OtherPercentile	Other percentile	A percentile not covered by any of the other percentile terms.
Beta1	Skewness	A measure for the asymmetry of a probability distribution of a variable.
Beta2	Kurtosis	A measure for the "peakedness" of a probability distribution of a variable.
ShapiroWilk	Shapiro-Wilk	Normality test statistics.
Other	Other	Use if the summary statistic type is known, but not found in the list.

DDI Controlled Vocabulary for Summary Statistic Type

Description

Details

Usage

Copyright and License