Free Police Entrance Test (POST / NPOST) Flashcards

Use March as the base because a percent change is measured from the earlier, starting value: (640 - 560) / 640 = 80 / 640 = 0.125, a 12.5 percent decrease. Using April as the base would give 80 / 560, about 14.3 percent, which overstates the drop because the smaller number becomes the denominator. The base is always the starting value, since the question asks how far the count moved from where it began.