Provide a bulleted summary of the history of how home-field advantage is determined for the World Series.

Context: Home-field advantage
World Series
The World Series used several different formats in its early years. Initially, it generally followed an alternating home-and-away pattern, except that if a seventh game was possible, its site was determined by coin toss prior to the sixth game. In 1924 the Series began using a 2-3-2 format, presumably to save on travel costs, a pattern that has continued to this day with the exception of a couple of the World War II years when wartime travel restrictions compelled a 3-4 format. From the start of the 2-3-2 format through the 2002 season, home-field advantage generally alternated between leagues each year. Prior to the 1994 strike, the National League champion received home-field advantage in even-numbered years and the American League champion in odd-numbered years; these were reversed for 1995–2002. That changed starting in 2003.

The 2002 All-Star Game ended in a tie, much to the displeasure of both fans and sportswriters, who complained about a lack of intensity and competitiveness on the part of the players. This hit especially close to home for Commissioner Bud Selig, as the game had been played in his home city of Milwaukee, Wisconsin. In response, to make the game's outcome more meaningful, in 2003, MLB began assigning home-field advantage in the World Series to the winner of that year's All-Star Game, which is typically held in mid-July.

Following the acceptance of a new collective bargaining agreement after the 2016 season home-field advantage in the World Series is no longer tied to the outcome of the All-Star Game, but instead is granted to the team with the better regular-season record. One exception was 2020, when all World Series games were played at a neutral site. The home-field advantage designation in the World Series was determined based on whichever pennant winner held the higher seed in its league, not necessarily the team with the better regular season record. However, in the event both pennant winners had held the same seeding number, only then regular season records would have determined the home team in Games 1, 2, 6, and 7.

Answer: Home field advantage for the World Series has been determined in the following ways throughout history:
- 1924 - 2002: Home field advantage simply alternated between the American and National Leagues each year.
- 2002 - 2016: Home field advantage was determined by the winner of the All-Star game.
- 2016 - Present: Home field advantage is determined by the team with the best record playing in the World Series.