A forest division judges its plantation work by the number of saplings put into the ground and reports that this number has doubled in three years, concluding that the division's forest is now growing twice as fast as before. The division's reasoning is most open to criticism because

What the division wants is forest; what it counts is planting, and the two are joined only so long as a planted sapling has a fair chance of living. Once the count is what the division is judged by, every cheap way of raising it — closer spacing, worse ground, planting after the rains have gone — raises the count and lowers the survival, so the reported doubling is consistent with less forest than before. A year-by-year breakdown would show the shape of the rise without touching what the rise measures; the species would matter to the forest's value; and raising the saplings in the division's own nursery bears on their cost and quality but leaves planted and living as far apart as ever.