But there are two important factors which aren't measured:
First, the effect of media coverage - or lack of it.
While LibLabCon issues get coverage, UKIP news largely relies on the bush telegraph - which is relatively unpredictable.
Second, "dawning". Many people who are disillusioned with the three main parties have become so by realising a few truths which hitherto had been somewhat hidden - e.g., expenses scandal, corruption and, on a more basic level, where the power lies.
This dawning is therefore one of truth. The funny thing about truth is that it spreads and, once spread, cannot be unspread. Lies and spin, on the other hand, must be constantly maintained and eventually are sunk under the weight of their own contradictions and absurdities.
Truth is winning, steadily.
How do you measure that?
- Voting Intention - 13th April (2nd poll with UKIP ahead of the LibDems)