It forecasts the Social Democratic Party of Germany (SPD)'s share of the popular vote based on the size of crude steel production in the old states that used to make up West Germany:[2] The Vote share of the SPD equals the Index of the crude steel production in the western federal states – measured in millions of tonnes – in the year of the federal election.There is a special rule for early elections.
However, an article attributed to Jakob Mierscheid, published on the German Federal Parliament's website provided a correction to the hypothesis, to take account of the special situation.
Since the elections had been brought forward, it was argued that the last months of the year should be discounted, yielding a steel production figure of 33.5 million tonnes.
Following the 2005 elections, an article was published by the statistical office of the state of Baden-Württemberg attempting to further refine the model in the form of the Mierscheid-Walla law.
This article also mentions promising but inconclusive attempts to replace steel production with other measures that exhibited a degree of apparent correlation, such as the export value of automobiles, employment levels in the field of legal advice, the price of coffee, and the number of accidents on town roads.