Methods, systems, and apparatus for predicting traffic data, including a method comprising: receiving data indicative of traffic data for a mediaplan during first and second time spans, the data representing numbers of unique entities that have interacted with a location during the first and second time spans; and using a function to predict third traffic data during the third time span. The function, when the arbitrary third time span does not exceed the first and second time spans, uses an exponential that includes a difference of dot products using natural logs of combinations of the time spans and first and second traffic data, divided by a difference of natural logs of the first and second time spans. Otherwise, the function uses a difference of dot products using combinations of the time spans and the first and second traffic data, divided by a difference of the first and second time spans.