Data engineering·Modelling for analysis
you summed the daily account balances across the month and got a number thirty times too big.
Semi-additive measure
Also calledsemi-additive fact, non-additive measure
A measure that can be added across some dimensions but not others — a balance sums across accounts but not across days, a ratio sums across nothing. It is the reason a snapshot table needs documentation about which aggregations are legal, and it is one of the most common sources of a confidently wrong dashboard. Marking measures as additive, semi-additive or non-additive in the model is the cheap prevention.