Re: Proper monetary rounding

The problem is that if there is any validity in the argument about trending upward, all this does it make it trend downward, which is not so clever if you are invoicing rather than paying out :).

In fact either kind of trending is a bug that comes from rounding when you shouldn't - instead, maintain maximum possible precision throughout the lifetime of your data and only round for the purposes of display and reporting alone - then either type of rounding won't be cumulative (i.e. "trend-forming").

-M

Free your mind

Comment on Re: Proper monetary rounding

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Re^2: Proper monetary rounding by blogical (Pilgrim) on Mar 08, 2007 at 03:14 UTC
Unless it's a lattitudinal trend across a large number of figures being calculated at the same time, all being derived from the same initial figure using the same formula, the sum of which consistantly exceeds the original figure due to a bias in the method of calculation. The point of the round to even method, if properly implemented, is that it recognizes the situations where error is likely to occur and neutralizes the tendancy to err in either direction. What you said about avoiding rounding- ie transformation of the source figure- is true. But it isn't necessarily a longitudinal problem.	[reply]
Re^3: Proper monetary rounding by Moron (Curate) on Mar 08, 2007 at 13:15 UTC
Bias has a continuous possibly increasing relationship with the input which has definite mean effect and is apt to have a Poisson distribution whereas rounding is discrete (only renders an effect at regular intervals) and does not render a mean overall effect. The probability of it being feasible to control one with the other is therefore zero. A better and tried and tested idea would be either feed back or feed forward a predictive or measured negation of the bias. -M Free your mind	[reply]