Official Count, on the other hand, only gave the full running totals by candidate, obtained by adding results as they were reported at the district council level. The order in which tallies were added was also different (see discussion elsewhere in this article). Finally, the behavior of the running tallies for the candidates was also very different: in the unofficial PREP count Calderón quickly overtook a very early lead by López Obrador and kept a diminishing lead until the end, while in the official count López Obrador led from the first report on, until Calderon overtook him near the end of the count. Statistical anomalies Physics professor Jorge A. López did a statistical analysis of the PREP results. There was some discussion among statistics experts, and other non-expert readers, about that analysis at a Columbia University blog on "Statistical Modeling, Causal Inference, and Social Science." In a July 19, 2006 comment to his July 17 article Professor James K. Galbraith writes: "For the PREP data, the issue of whether we are seeing 'cyberfraud' or a more traditional kind is a red herring, in my view. I did not use the term 'cyberfraud' in my essay. In principle, the anomalies observed could be generated electronically, or manually. Or, to be complete, they could have innocent explanations; however so far these have not been provided." Professor Galbraith holds the Lloyd M Bentsen Jr chair of government/business relations at the Lyndon B Johnson school of public affairs, the University of Texas. Physics professor Luis Mochán also did several analyses of the PREP results; one involved the evolution over time of the PREP results. An August 2, 2006 AlterNet article writes: "Mochán notes that these statistical anomalies aren't definitive proof of anything." In his book El mito del fraude electoral en México ("The myth of the electoral fraud in Mexico") Fernando Pliego Carrasco considered the timing of the results and related them to the "marginalization degree" of the electoral districts, as determined by the Consejo Nacional de Población's 2005 census. The marginalization degree of a district is a measure of the affluence of the district, its infrastructure, population centers size, and educational level. Very low marginalization represents an affluent district with good infrastructure and large, educated population. Very high marginalization represents a poor district with little or very poor infrastructure, and small, largely uneducated population. The table below shows the results of the PREP,