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Friday, September 17, 2004

Rasmussen knows Robert Guesses

Eric Rasmussen is going to discuss data on good days (of the week) for Kerry and Bush. The Rasmussen Report has good data on this by now. I am going to guess that weekends are good for Kerry and especially Sunday. If there is a Sunday effect, it is bad news for Kerry. I would guess it would be churchgoers are undersampled on Sunday (they are in church). They are known to be more likely to vote for Bush and won't be in church on November 2nd.

The other day of the week effect might be working vs non working women. I'm sure pollsters make sure they roughly match the population on gender and age. I would guess calling during the week, one oversamples housewives and welfare moms. The number of welfare moms has dropped sharply since the last Presidential election the pollsters got right (1996). I would guess weekdays good for Bush because housewives are oversampled.

I think pollsters really should call unanswered numbers after normal working hours, since polls stay open after normal working hours. I don't know if they do.

Now I am going to check Rasmussen to see if my guess on red days and blue days is correct.

Update: I'm right ! For some utterly mysterious reason, Rasmussenreports reports the average by release day "The data presented at the table to the left is based upon release days. Our data is released as a three-day rolling average, so the data is collected on the three nights prior to the release day (i.e.--results released Thursday use interviews conducted on Monday, Tuesday, and Wednesday nights)."

This means that Rasmussen reports the average of moving averages. This is crazy, Give 16,500 observations per week day, there is no need for a moving average. It is not possible to extract the results by day of polling from the moving average (and uninvertable ma). This not only makes it much more difficult to figure out what the numbers means but also reduces the precision of the following estimate.
On Thursday, Friday and Saturday, Rasmussen reports the average of results for 3 week days. on average of average of moving average, Bush is up 2 2/3 % on such days. On Wednesday and Sunday, Rasmussen reports results from two weekdays and one weekend (respectively Sunday and Saturday). Kery is up on average 0.2%. On Monday and Tuesday, Rasmussen averages over two weekend days and one weekday. Kerry is up on average o.35%. On average to the fourth replacing a weekday with a weekend day helps Kerry slightly more than 0.3o8%. Each day is divided by 3 (in the moving average) so the estimated difference
(Bush-Kerry)_weekday - (Bush-Kerry)_weekday is slightly more than 0.924%. This is not a huge number.

However the standard errors of the release day averages are less than half of a percent (19/7*root(10)). The overlap of subtracted days and further averaging makes ... well the standard error of the 0.924% estimate very hard to calculate but small.

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