In the first decade following the founding of the British Labour party, the number of people regularly voting for Labour increased fivefold  The number of committed Labour voters increased a further fivefold during the party' s second decade
Since the increase was thus the same in the first as in the second decade, the often-made claim that the Labour party gained more voters in the party' s second decade than in its first is clearly false
fails to specify dates necessary to evaluate the truth of the conclusion, even though the argument depends on distinguishing between two time periods