Monday, October 29, 2012

All of Those Polls


There's a new poll every few seconds, it seems, and all of them pointing in different directions. Assuming that all of them are polls of likely voters, it seems to me that the largest factor giving rise to the variations would be the weight accorded to the three voting groups, Democrat, Republican and Independent, whether or not they adjust for that factor.

Sometimes the D/R/I split for a given poll is announced, and sometimes not. Frequently, however, along with the overall result (Romney by 1, Obama by 2...) the poll will also provide the split among independent voters. When that occurs, with a couple of relatively safe assumptions, you can figure the D/R/I split yourself with my handy dandy spreadsheet.



First, open MS Excel. Put in your column and row labels, just like I did. Then the fun part starts. In the column labeled "Total Voters" enter estimates of the D/R/I split, but only for Dems and Reps. The entry for Ind shoud the 100 less the sum of the first two rows. Remember, boys and girls, this is only an estimate.

Next comes our first assumption: That 95% of the members of each group is already committed to the candidate of his or her choice. So in the column labeled "5% undecided voters", tell the spreadsheet to muliply the appropriate row of "total voters" by 0.95.

Then comes our second assumption: That 90% of party-affiliated voters will vote for their own candidate. So in the column labeled "%age voting R" enter 0.10 in row 1 (D voters) and 0.9 in row 2 (R voters). In row 3 (I voters) enter the percentage given by the poll as voting R. Similarly, in the column labeled "%age voting D" enter 0.90 in row 1 (D voters) and 0.1 in row 2 (R voters). In row 3 (I voters) enter the percentage given by the poll as voting D.

Next, in the column labeled labeled "votes R", tell the spreadsheet to muliply the appropriate row of "decided voters" by the entry in the same row in the column to the left. And in the column labeled labeled "votes D", tell the spreadsheet to muliply the appropriate row of "decided voters" by the entry in the same row in the column to the left.

Finally, have the spreadsheet prepare a total of the "votes R" column and the "votes D" column, and then, in the last column, tell the spreadsheet to subtract one total from the other.

Now, boys and girls, we are ready to play. Remember the estimated D/R/I split we entered in the "total voters column"? Well, to figure the D/R/I split in the poll you are trying to figure out, simply adjust the D and R amounts until the last column of the spreadsheet matches the overall result given by that poll. Voila, this is likely to be very close to the D/R/I split in the poll, even if the pollster doesn't provide that information. Your mileage may vary.

You can do this at home. No adult supervision is required. Send lots and lots of money to me at Man with Shovel and I will send you your very own spreadsheet.

But wait! There's more!

Respond before November 6, 2012 and I will double your order at no extra charge! Not even shipping and handing!

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