On the Cutting Edge

The methods that Chris and I discuss in this clip are another promising direction for the survey and polling industry.

They constitute a serious response to at least two of the main pitfalls for election prediction that we have encountered this week. They enable pollsters to get credible constituency-by-constituency estimates even:

• without serious constituency-by-constituency polling, which is prohibitively expense to collect
• when most people refuse to engage with their surveys

There is one key assumption and one key data requirement that enable the use of these methods. First, we need to be able to classify people into groups that display reliable within-group voting patterns. These groups may be pretty complicated amalgams of a wide array of characteristics. For example, one such group might be university educated black females in their thirties living alone in the northwest and working in the tourism sector. We don’t have to assume that all the people in such a group have identical preferences. But we do need to assume that people with these characteristics display stable tendencies that do not depend importantly on some other unmeasured characteristics. Second, we need to have reasonably accurate constituency-by-constituency information on the numbers of voters possessing each bundle of characteristics. A good census can provide such information.

With these two ingredients in place we can construct constituency-by-constituency results by multiplying the tendencies of each voter type by their numbers within the constituency and adding these products up. I’ll take you through a sample calculation along these lines in step 2.20.

Discussion

No method is a panacea. They all have weaknesses.

So what do you think are the weaknesses of this particular method?