Independence Day, a.k.a., July 4, follows Memorial Day, a.k.a. the last Monday in May, this year May 28, but both days are used as forecasters of which teams will finish the season in first place. The advent of wild cards has muddled the reliability of these barometers, or has it?

I looked at MemoriaI Days past in a column about six weeks ago and found, courtesy of Elias Sports Bureau, that of the 97 teams that were in sole possession of first place from 1995 through last season on Memorial Day, 56 finished in first place. That computes to 58 percent.

The period began with 1995 because that was the year wild cards, one in each league, were created.

The ratio of winners does not change much when July 4 is used. Again from 1995 through last season, Elias found, 59 of 97 teams holding division leads alone on July 4 won those division titles. The division winners represented 61 percent of the July 4 division leaders.

It comes as no surprise that more July 4 leaders won division titles than Memorial Day leaders because nearly six more weeks of the season had been played and the leaders had less time to lose their leads.

In the case of July 4, however, I asked Elias to go further and include all season from 1900. These were the results:

• 1900 through 2011: Of 357 league or division leaders, 226 finished the season in first (63 percent).
• 1900 through 1968 (last season before division play): Of 158 league leaders, 106 finished in first (67 percent).
• 1969 through 1993 (pre-wild cards): Of 105 division leaders, 61 ended the season in first (58 percent).
• 1995 through 2011 (wild-card era): Of 97 division leaders, 59 won their division titles (61 percent).

Do any of these figures prove anything? If they do, it’s conflicting.

Enough July 4 and Memorial Day leaders have not finished in first place, showing that a division title is not guaranteed to a first-place team. However, based on the percentages, the chances of winning the title are better for a division leader than for a team that does not lead its division on either of those days.

The teams that led their divisions upon waking on Wednesday (July 4) were the Yankees, the White Sox, the Rangers, the Nationals and the Giants. The Pirates and the Reds were tied for first in the National League Central.

Those six first places represented a significant change from Memorial Day. The Rangers and the Nationals also led on that day, but the Indians and the Dodgers were in first place in their respective divisions, the Reds were alone in theirs and the Orioles and the Rays were tied for first in the American League East.

The Dodgers and the Giants experienced the greatest movement in the standings between the two measurement dates, the Dodgers squandering a 7½-game lead over the Giants and slipping half a game behind them. However, on July 4, they switched positions again.

But the Pirates have to be the most intriguing team. A perennial loser, the Pirates didn’t make the morning-of-July 4 list because they were tied for first with the Reds. That day, though, they won and the Reds lost, giving them first all to themselves.

On July 4, 1992, the Pirates were in first place with a 5½-game lead en route to their third straight division title. A year later they were in fifth place, 14 ½ games out, with a 38-42 record en route to the first of 19 consecutive losing seasons.

The best example in recent years of a team that has defied the percentages is Philadelphia. A five-time winner of the N.L. East, the Phillies were in first place July 4 only three of those seasons. In 2007 they were in third place 4½ games behind, and in 2010 they were in third, five games out.

That is not to say those two comeback seasons can serve as inspiration for the Phillies this season. On July 4 this year they were 12 games from first in last place and had not been able to find even a small piece of the offense missing while Ryan Howard and Chase Utley were recovering from injuries.

Utley is back and Howard is close to getting back, but the Phillies are probably too far gone to be able to recover and make up all of the ground they have lost.

Then again, they were the beneficiary of a good omen on July 4. They were losing to the Mets, 2-0, after six innings but erupted for three runs in each of the last three innings and gave Cliff Lee his first victory of the season.

Besides watching to see if the Phillies can somehow play well enough in the second half even to win a wild-card spot, the most interesting developments in the second half will most likely involve the Pirates and the Nationals.

After games of July 4, those two teams had improbably the best won-lost records in the National League. The environment of first place is new to the Pirates, but the Nationals have been in first place in the N.L. East for the last six weeks and held the position for significant time before that period.

By now they are used to it and don’t have to act as it were something new and unusual. Their manager, Davey Johnson, is familiar, too, with running a first-place team, having won the 1986 World Series with the Mets and reached the league championship series three other times.