# PercentofTotalChange

This aggregate
should be understood as “Change in (Percent of Total)”, not as “Percent
of (Total Change)”. It is the result of calculating PercentofTotal on
two different columns, and then calculating the difference between them.
The result is presented as the difference in *percentage units*,
n.b.

This aggregate is typically used for comparing PercentofTotal based on current values, to PercentofTotal based on previous values. Therefore, the column specified as “Weight Column” in the settings, should be the column containing previous values.

The aggregate value is calculated as a ratio between 0 and 1 and will be presented as a percentage value by applying a percent format string in the aggregation settings. Optionally, you can emphasize that the value is a percentage units by customizing the format unit, for example: 0.00%'-units'.

Sample

ID |
Current Value |
Previous Value |
Total of Current |
Total of Previous |
Percent of Total (current) |
Percent of Total (previous) |
Percent of Total Change |

A |
25 |
25 |
100 |
125 |
0.25 |
0.20 |
+0.05 |

B |
45 |
65 |
100 |
125 |
0.45 |
0.52 |
-0.07 |

C |
30 |
35 |
100 |
125 |
0.30 |
0.28 |
+0.02 |