The terms used in this article to identify current quarterly estimates of GDP and GNP are the same as those BEA uses in its news releases and SURVEY articles. The current quarterly estimates consist of a set of three successive estimates: The first, released 1 month after the end of a quarter, is the "advance" estimate; the second, released 1 month later, is the "preliminary" estimate; and the third, released 1 month after that, is the "final" estimate. The article also uses the term "later current estimates," which refers to only the "preliminary" and "final" estimates. The term "latest available estimates" refers to the latest estimates used by each study cited in the article for comparison with the current estimates; in general, the "latest available estimates" are those that incorporate the latest comprehensive and annual revisions of the NIPA's that were conducted prior to the completion of each study (see the note to table 2).
The terminology for the current estimates described in the preceding paragraph has been used by BEA since July 1988; other terminologies were used prior to that. The following tabulation shows the equivalent terms that BEA has used either in news releases and SURVEY articles or in its revision studies.
| Prepared in: | (1) | (2) | (3) | (4) |
| First month | Advance | 15-day | Preliminary | Preliminary |
| Second month | Preliminary | 45-day | 1st revision | Final |
| Third month | Final | 75-day | 2nd revision |
The present terminology is shown in column 1. The terms in columns 2 and 3 were used interchangeably from 1974 to 1988. The terms in column 2 described the elapsed time to complete the estimates after the end of a quarter: The first, about 15 days after; the second, about 45 days after; and the third, about 75 days after. (This terminology was discontinued in 1988, when BEA began releasing its estimates later in the month in response to a change in the schedule for processing monthly merchandise trade forms.) Prior to 1974, only the 15-day and 45-day estimates were prepared, and the terms shown in columns 2 and 4 were used. Prior to 1958, only the 45-day estimate was prepared. (From 1965 to 1985, BEA also prepared a "flash" estimate (also called the "projection" or "minus 15-day" estimate) about 15 days before the end of a quarter; this estimate is not included in this study.)