Comments on: Mayoral Election Finance 2014: Charts, Maps it's like being there Tue, 16 Sep 2014 04:56:38 +0000 hourly 1 By: Dave Askins Dave Askins Sat, 26 Jul 2014 01:57:53 +0000 Re: “…cut that money out and see what the mean/median are…”

One reason the median and mean are often reported together as measures of central tendency is that the median is not nearly as sensitive to outliers as the arithmetic mean. From the fact that a dataset (like Petersen’s contributions) has a mean of $334 but a median of $100 you can tell there are outliers on the high side included in that data set.

Reporting both measures of central tendency using all the data is, I think, a better strategy than selectively eliminating data and then computing whatever “average” seems appropriate.

On a related point, note that there are several outliers on the low end in Taylor’s dataset. Why anyone contributes $1 to a political campaign is beyond me, but the effect of that contribution is to drive down the arithmetic mean. Same with the several $5 donations – which Taylor’s campaign on at least one occasion (after close of books, however) explicitly solicited in that amount. Do you say, “Oh, well, that’s not a legitimate donation for my analysis, so I’ll just eliminate it.”? My answer is no.

By: Kai Petainen Kai Petainen Sat, 26 Jul 2014 01:40:05 +0000 With CM Petersen, the $30,000 that her and her husband gave are such outliers…. cut that money out and see what the mean/median are.