September 7, 2004

Hausmann and Rigobon: The incomprehensible, the evident and the damning

Hausmann and Rigobon's paper on the evidence of fraud in the Recall Referendum makes three basic arguments. Instant reaction.

1.The Incomprehensible.
Hausmann and Rigobon claim that a sophisticated statistical method comparing exit poll data and Nov. 2003 signature totals with CNE results generates evidence of fraud.

They set out to "develop a statistical technique to identify whether there are signs of fraud in the data." This is how they describe the method they used:

"We depart from all previous work on the subject which was based on finding patterns in the voting numbers. Instead, we look for two independent variables that are imperfect correlates of the intention of voters. Fraud is nothing other than a deviation between the voters' intention and the actual count. Since each variable used is correlated with the intention, but not with the fraud we can develop a test as to whether fraud is present. In other words, each of our two independent measures of the intention to vote predicts the actual number of votes imperfectly. If there is no fraud, the errors these two measures generate would not be correlated, as they each would make mistakes for different reasons. However, if there is fraud, the variables would make larger mistakes where the fraud was bigger and hence the errors would be positively correlated. The paper shows that these errors are highly correlated and that the probability that this is pure chance is again less than 1 percent."

The statistical methods employed to come to this conclusion are sophisticated beyond my ability to analyze. I imagine it would be possible to argue that Sumate and Primero Justicia's exit polls were so flawed, that what we have here is a classic case of JIJO: Junk In, Junk Out. But since I couldn't understand the analysis, I can't really judge it - I have to take Hausmann and Rigobon at their word.

2-The Evident
The analysis discards the Si-cap hypothesis.

This had always seemed to me as a weak argument, partly because the evidence was ambiguous, but mostly because it made no sense to me that CNE would plan out a big, complex, sophisticated fraud operation and then institute a mechanism that would leave such an obvious footprint in the data. I never thought it added up, and neither do Hausmann and Rigobon.

3-The Damning
The study provides statistical evidence that the sample chosen by CNE for the cold-audit was demonstrably not random.

This is the most eye-catching conclusion to the study, and of special concern to me, since I'd consistently held the view that the cold-audit was the strongest card in CNE's hand. If the audit sample was not randomly selected, and the non-randomness fits in neatly with the rest of the fraud hypothesis, then it's the first solid evidence of fraud I've seen yet.

Let me quote again from Hausmann and Rigabon's summary of their argument:

"First of all, the Carter audit, conducted on August 18, was based on a sample of about 1 percent of the ballot boxes. According to the Carter Center, the audit went flawlessly, except for the fact that the Head of the Electoral Council was not willing to use the random number generator suggested by the Carter Center but use instead its own program run on its own computer. At the time, this seemed odd, given that the objective of the audit was to dispel doubts.

"The paper finds that the sample used for the audit was not randomly chosen. In that sample, the relationship between the votes obtained by the opposition on August 15 and the signatures gathered requesting the Referendum in November 2003 was 10 percent higher than in the rest of the boxes. We calculate the probability of this taking place by pure chance at less than 1 percent. In fact, they create 1000 samples of non-audited centers to prove this.

"This result opens the possibility that the fraud was committed only in a subset of the 4580 automated centers, say 3000, and that the audit was successful because it directed the search to the 1580 unaltered centers. That is why it was so important not to use the Carter Center number generator. If this was the case, Carter could never have figured it out."

If this is right - and I have no reason to doubt it, at this point - this would dismantle the main reason to think there was no fraud: namely, that there was no way for CNE to tamper with the paper-ballots after the sample-selection but before international observers got there. There was no way to do it, as I'd thought...but there was also no need to do it: they already knew that the boxes audited would come from "clean" tables!

I've always taken the view here that I don't know if there was fraud or not, cuz I'm not omniscient. What's hard, as a commited antichavista, is to try to come to a judgment on this matter based on evidence rather than ideology or wishful thinking. The Haussman and Rigobon paper is significant precisely because it gives us the first bit of evidence that something was not right with the cold-audit. Having taken the cold-audit as the primary reason to think the election was fair, the paper obviously requires that I go back and reconsider.

One last consideration: if Hausmann and Rigobon are right, then there was no reason for CNE to go back and alter the paper ballots. If CNE did not tamper with the paper ballots, then it follows logically that even now a recount of paper ballots could detect fraud. For many reasons (the security codes printed on each paper ballot by the smartmatic machines, the fact that thermal paper fades over time, the daunting logistics involved, etc.) it would be very hard for CNE to go back now and tamper with the ballots. So even at this late date, it strikes me that the truth is certainly out there: sitting in those ballot boxes, slowly decaying into unreadability.

As a final note: as always, I'm eager to hear a reasoned explanation of how and why it is that Hausmann and Rigobon's analysis is wrong. I am much less eager, however, to hear ad hominem attacks against them, or blithe dismissals of anyone who would spend time inquiring into the fraud hypothesis.

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