Aggregation

An aggregation combines multiple numerical values of a criterion in one value.

Criteria have a default aggregation mode based on their data type. However, you can configure the aggregation mode during evaluation, as well.

Table of aggregation modes

Abbreviation

Description

Sum

Sum of values, default for integers

Avg

Average, default for floating point numbers

Min

Minimum

Max

Maximum

Count

Number of values of a criterion (in PPM, this is also called relevance)

Stddev

Standard deviation

Quantiles

Quantiles, e.g., median

A query can consist of multiple aggregations of a criterion or of multiple criteria. Aggregations are run independently.

Example

In the example, adding the individual values of the Costs criterion results in the total cost of maintenance (sum = 58) of all hosts.

Host

Maintenance

Costs

Win

Virus scanner

12

Win

OS upgrade

14

Mac

OS upgrade

14

Mac

HDD change

18