Our accuracy rating of "94.7%, four quarters out" applies to our year-end forecasts that were in place as of Jan. 1 of the same year.
To calculate our 2017 forecast accuracy rating, for example, we looked at the forecasts we had in place as of Jan. 1, 2017, versus the actual year-end 2017 results. The accuracy rating is derived from the deviation between the actual results and our forecast; e.g., if year-end actuals come in 2.0% above (or below) the figures we had forecasted as of Jan. 1, our accuracy rating would be 98.0%.
We cite 94.7% as our accuracy rating from the 1980s up to now because our annual forecasting audit has not returned a rate below 94.7% throughout that time.
For more information on our forecast accuracy, visit our site here.