The Celtics keep insisting it’s not a sure thing that the team with the worst record will win the NBA Lottery. Unfortunately, they’re right. Judging by history, even if Greg Oden and Kevin Durant declare for the draft, neither will likely suit up next season for Boston.

The lottery is weighed in favor of the worst teams, but not to the point where losing automatically pays off.

From 1966-1984, the teams with the worst records in each conference flipped a coin to determine which one would draft first, then draft continued by inverse order of record. The lottery was first held in 1985, then restructured in 1990 to improve the chances of teams with the worst records. Orlando won the 1993 lottery with the 11th and best record of any lottery team, so the lottery was readjusted in 1994. Since then, the top pick has still gone to the team with the best chance of winning only three of 13 times and to the team with the second-best chance just once. Last year, Toronto won the lottery with the fifth-worst record and only an 8.8 percent shot of winning. The year before, Milwaukee won with the sixth-worst record and just a 6.3 percent chance.

If the Celtics enter the May 22 lottery with the NBA’s second-worst record, a position they currently hold, they would have a 19.9 percent chance of winning and an 18.8 percent chance of remaining second. The team with the second-worst record has finished second in the lottery only once. Usually, the second-worst team drops to third or further. The most spots a team can fall in the lottery is three. The lottery determines the top three spots, then teams are placed in order by record.

History indicates the Celtics would be better off dropping to the third-worst record because teams with the third-worst records have won the lottery four times, the most of any position. No team with the fourth-worst record has won the lottery, but teams with the fifth-worst records have won three times.

Ten years ago, the Celtics had by far the best chance to win the lottery after finishing with the NBA’s second-worst record. Vancouver owned the worst record, but wasn’t eligible to win the lottery in either of its first two NBA seasons per order of its expansion agreement. The Celtics had also acquired the first-round pick of Dallas, which finished with the sixth-worst record. So the Celtics enjoyed a 36.31 percent chance of winning the lottery — nearly twice what the team with the second-worst record will have this year. But San Antonio, with a 21.60 percent chance, won the lottery and drafted Tim Duncan. Philadelphia, with only a 12.24 percent chance, finished second and took Keith Van Horn. The Celtics ended up with only the third and sixth picks and selected Chauncey Billups and Ron Mercer. They made things worse by trading Billups midway through his rookie season. Mercer never did much.

The 1997 NBA Draft was not an especially productive one. Only Duncan, Billups and Tracy McGrady have made All-NBA first, second or third team. Too bad the Celtics didn’t keep Billups and draft McGrady instead of Mercer.