There may be 5 or 6 ballots necessary to elect the President of the Republic; as for the names, the most realistic scenario is the one that sees a shared name both from the center-left and M5S and from the center-right; if this does not happen, 40% of independent voters at the estimated time could increase and be decisive in making the votes converge on the outgoing president, Sergio Mattarella: this is how mathematics comes into play in analyzing the situation relating to the elections for the Quirinale. The mathematician Giovanni Sebastiani, of the Institute for the Applications of Calculation ‘M. Picon’, of the National Research Council (Cnr), is studying the numbers and identifying trends.
“Even before the beginning of the current elections for the President of the Republic, from the analysis of the, albeit scarce, data of the previous elections it was known that the median value of the number of ballots required for the election is 5”, observes the expert. Added to this is the fact that the progressive decrease in blank ballots in the 3 ballots is described “with an excellent approximation by a linear model with an average rate of decrease of 130 units per ballot”.
Beyond the causes that have produced the phenomenon, “if they are unchanged (groups permitting), the model predicts that at the sixth vote the number of blank ballots will be less than 1%. So it is likely that the election will take place on the fifth or sixth ballot “.
Regarding the name of the next president, Sebastiani conducted a simulation study based on the following elements: “the stability of the current government”, “Draghi’s recent action, which shows his concrete desire to run”, “the recent declaration by the center-right to prefer him to his current position, with the relative implications for his electors “and the fact that Draghi did not get votes in the last ballot. The last vote also shows that, “excluding the blank and null ballots, the dispersed votes, and the approximately 60 votes of the Brothers of Italy, result in approximately 400 votes for candidates who have not yet been officially supported by any group”: data interpreted as a “40% of voters who show the potential willingness to vote independently of the indications of their group”.
From these elements, 3 scenarios were produced: the first foresees “4 possible candidates: Draghi supported by the center-left block-M5S, a candidate of the center-right, Mattarella, and the category ‘other’; the second foresees 5 candidates: Draghi, one of the center-right , one of the center-left-M5S, Mattarella and ‘other’; the third includes Draghi, a common candidate for the center-left-M5S and center-right, Mattarella and ‘other’.
In the simulations, moreover, the voters were divided into 3 groups: center-right (455 units), center-left-M5S (425), and ‘other groups’ (100 units, obtained by difference from the value of about 980 voters of the three votes carried out) .
“For each of the scenarios considered, with the values assigned to the different probabilities that a voter of each of the possible groups has of voting for one of the possible types of candidates, it appears that the only scenario that guarantees significant chances of obtaining the quorum of the absolute majority ( 505 votes), is the last one, the one with a common center-left-M5S and center-right candidate. In the event that this scenario is not realized – concludes the mathematician – it is natural to foresee a further increase in the probability of snipers in favor of Mattarella, which would likely lead to his re-election. “