A statistical argument on Poe’s disqualification

The controversy involving the Senate Electoral Tribunal’s 5-4 decision upholding Sen. Grace Poe’s status as a natural-born Filipino continues, and the issue is expected to be elevated to the Supreme Court anytime soon. The decision threw out the petition lodged by Rizalito David but the three Supreme Court justices in the SET voted in its favor, leading some observers to believe that the petition has a solid legal basis. On the other hand, five of the six senators in the SET voted on the basis that a foundling found in the Philippines has all the rights of a full-fledged natural-born Filipino, including the right to seek the presidency.

Reading the 32-page main decision of the SET, one will find it quite interesting to see how the majority arrived at its vote. In Justice Antonio Carpio’s words, the majority relied on a “sentimental plea that conveniently forgets the express language of the Constitution reserving those high positions, in this case the position of senator of the Republic, exclusively to natural-born Filipino citizens.” On this note, let me offer a statistical argument that may possibly help in settling the issue.

In inferential statistics, specifically in hypothesis testing, there are two contending hypotheses: the null hypothesis (H0) and the alternative hypothesis (H1), in which the objective is to gather evidence through sampling that would either support or reject one of the hypotheses.

There are four possible courses of action: 1) Accept a true H0; 2) reject a false H1; 3) Reject H0 when in fact H0 is true; and 4) accept H1 when in fact H1 is false.

If one commits No. 3, then one commits a Type I error. On the other hand, if one commits No. 4, then one commits a Type II error. Since the procedure only involves a sample from a population of interest, then no one would know if H0 is true or if H1 is false. Hence, one is bound to make an error of either Type I or Type II. Since these two errors are mutually exclusive, one has to weigh which type of error he or she is willing to commit. Of course, the decision depends on the cost of committing such an error.

Let us apply those arguments on Poe’s case. Let us remember that the senator’s being a foundling is a fact. Hence, according to relevant laws, she is a Filipino. The only point of disagreement is whether Poe is natural-born or not natural-born. Let H0 be such that Poe is natural-born and H1 be such that she is not natural-born. It is worthy to point out that these are the only possibilities.

From these hypotheses, as in the case of hypothesis testing, there are four possible decisions that the Supreme Court may render—Decision 1: Declare that Poe is natural-born when in fact she really is natural-born (one or both of her parents are Filipino); Decision 2: Declare that Poe is not natural-born when in fact she really is not natural-born (both of her parents are not Filipino); Decision 3: Declare that Poe is not natural-born when in fact she really is natural-born; Decision 4: Declare that Poe is natural-born when in fact she really is not natural-born.

Since Poe was not able to establish her parentage through DNA testing, the Supreme Court cannot hope to render Decision 1 or Decision 2 with certainty. In the absence of DNA testing, there is great likelihood that the Supreme Court will make an error. Consequently, it would have to make either Decision 3 or Decision 4, which corresponds to Type I error or Type II error, respectively. Now, which of these two types of errors is more costly to make from the viewpoint of the Supreme Court? If it renders Decision 3, then the highest court of the land restricts an individual from exercising her legitimate right. On the other hand, if it renders Decision 4, then it allows a Filipino who is not natural-born to run for the presidency, and who may possibly become the president of the land—a clear violation of the Constitution.

Finally, it is worthy to point out that Decision 3 affects only a single individual whereas Decision 4 affects the whole nation. Consequently, the Supreme Court will choose in favor of Decision 3, the less costly of the two decisions—hence the disqualification of Grace Poe from seeking the presidency.

Jonald P. Fenecios obtained his PhD in mathematics at the Ateneo de Manila University. He is the current chair of the Department of Mathematics of the Ateneo de Davao University, where he is also associate professor.