It was well known that tra­di­tion­al polling was hav­ing prob­lems. The numb­ing ef­fect of bil­lions of tele­market­ing calls and the ad­vent of caller ID and voice mail had re­duced re­sponse rates (the per­cent­age of com­pleted in­ter­views for every hun­dred at­tempts) from the 40s a couple of dec­ades ago to the high single di­gits. As they struggled to get truly rep­res­ent­at­ive samples, poll­sters “weighted” their data more than ever be­fore, mak­ing as­sump­tions of what the elect­or­ate would look like on elec­tion days that were weeks, months, or even a year or more away.

...snip...

The re­li­ance, or per­haps over­re­li­ance on ana­lyt­ics, may be one of the factors con­trib­ut­ing to Clin­ton’s sur­prise de­feat. The Clin­ton team was so con­fid­ent in its ana­lyt­ic­al mod­els that it op­ted not to con­duct track­ing polls in a num­ber of states dur­ing the last month of the cam­paign. As a con­sequence, de­teri­or­at­ing sup­port in states such as Michigan and Wis­con­sin fell be­low the radar screen, slip­page that that tra­di­tion­al track­ing polls would have cer­tainly caught.

Ac­cord­ing to Kantar Me­dia/CMAG data, the Clin­ton cam­paign did not go on the air with tele­vi­sion ads in Wis­con­sin un­til the weeks of Oct. 25 and Nov. 1, spend­ing in the end just $2.6 mil­lion. Su­per PACs back­ing Clin­ton didn’t air ads in Wis­con­sin un­til the last week of the cam­paign. In Michigan, aside from a tiny $16,000 buy by the cam­paign and a party com­mit­tee the week of Oct. 25, the Clin­ton cam­paign and its al­lied groups didn’t con­duct a con­cer­ted ad­vert­ising ef­fort un­til a week be­fore the elec­tion.

In fact, the Clin­ton cam­paign spent more money on tele­vi­sion ad­vert­ising in Ari­zona, Geor­gia, and the Omaha, Neb­raska mar­kets than in Michigan and Wis­con­sin com­bined. It was Michigan and Wis­con­sin, along with Pennsylvania (the Clin­ton cam­paign and al­lied groups did spend $42 mil­lion on tele­vi­sion in the Key­stone State), that ef­fect­ively cost Demo­crats the pres­id­ency.

http://cookpolitical.com/story/10205