Evidence on the Tory Strategy of Targeting Marginals
By Can be found here. In short, it looks to be successful. Longer, the BPIX poll that was released yesterday is being touted as having a large enough sample size to say something about the marginals that the Tories are targeting, and claims the swing in said seats is significantly higher than the national swing.
Note, this poll shows a Tory plurality of only 2% over Labour, whereas over the past several weeks YouGov has settled into a 5% to 6% range, with that one “blip” of 2% last weekend. A uniform swing would produce a C 252 / L 309 / LD 56 distribution — in all likelihood a Labour minority government. In order to gain a plurality share of the seats, the Tories would have to take 29 additional seats off of Labour (not the Lib Dems, but Labour); to obtain an outright albeit narrow governing majority, they would need 74 seats in addition to what a uniform national swing would predict.
Unfortunately, nothing on this poll appears to be available aside from the superficial information I’ve discussed above. I’m especially keen to know how, and to what degree, the marginals were oversampled. While an N of 5655 is impressive for a poll of this nature, a purely random sampling would equate into an N of 8.7 for each of the 650 constituencies. Of course, they didn’t sample in purely random fashion as some form of stratified sampling was certainly employed, but still, how large can the N be for the 75 or so odd marginals that the Tories are targeting?
