Wikipedia:Did you know/Fivefold day explanation

G1: To calculate fivefold expansion since a specific day, which I will call July 18, 2008, for definiteness: 1. Count the characters in the prose-only portion of the current version. 2. On the article's history screen, click the latest time stamp before July 18, not the first time stamp for July 18. 3. Divide by the prose-only characters on that screen.

To explain the counter-intuitive step 2, I emphasize the difference between an edit's change, which you see by clicking "prev" on the history page, and an edit's result, which you see by clicking the time stamp on the history page. Although an edit's change and an edit's result are listed on the same line, the edit's change really comes between that edit's result and the previous edit's result. Similarly, an edit's result really comes between that edit's change and the next edit's change, even though an edit's change and an edit's result are shown on the same line.

Example. On January 1, 2006, a 100 character stub is created. At 1:00 on July 18, 2008, the 100 characters are expanded to 1000 characters. An hour later at 2:00 July 18, 2008, the article is further expanded to 2000 characters. When I say it that way, the expansion is clearly 20x (or equivalently, 95% new) and qualifies for Did You Know. But to count the 100 characters, they wouldn't be listed as 1:00 July 18. The 100 characters existed on July 18 before 1:00, but the 100 characters were the result of the previous edit. So you would have to click the 2006 edit to count the 100 characters, even though 2006 is much too old for Did You Know. If you made the mistake of clicking the first edit for July 18, you would get the result of that first edit and therefore miss the change of that edit, and count 1000 characters, resulting in 2x expansion and an unjust disqualification.