WR Dataset Notes

WR Dataset Notes as of June 2025

Data compiled from publicly available sources including Wikipedia (CC BY-SA 4.0) and publicly available competition result sheets. Dataset licensed under CC BY-SA 4.0.

Sources:

• The only available source of all historical swimming world records is Wikipedia.

• I contacted World Aquatics, the International Swimming Hall of Fame, SwimSwam, and Swimming World (the latter two are the main swimming news outlets); the first three responded confirming that Wikipedia is the go-to source for this data.

• Wikipedia often has links, and I was able to back up information in the dataset, with additional research on the World Aquatics website.

• World records in this dataset are only individual.

  • Individual WRs can be set during a relay but only during the first leg (based on a regular start as opposed to a relay start that gives the swimmer an advantage).

  • WRs set on the first leg of a relay can only be backstroke (medley relay) and freestyle (Freestyle relay).

• The following bullets detail other efforts I took to make this data usable and as reliable as possible.

• The first post is published BY THIS DATE; additional WRs are tracked as well, and future posts could be based on these updates and on new WRs set.

Fun Random Notes

• Goggles were not used until around the 1970s (Mark Spitz!).

• Charles Daniels and the swimmers of the early 1900s were responsible for bringing the modern Olympic swimming movement to the US by doing very well.

  • They competed often in lakes and estimated distances in yards – some of these records are not captured here, since records were spotty and not always reliable.

  • Their contribution to the sport is incredibly important.

  • “The Watermen” by Michael Loynd, 2022 is a great resource and account of the early US Olympic swimmers.

• 1912 saw the introduction of electronic timing.

• 1924 was the first year to use a 50-meter pool with standard marked lanes.

• Originally, swimmers dived off from the wall; blocks were used starting at the 1936 Games.

• In the 1950s swimmers started using flip-turns.

• 1908 saw a 100-meter pool built.

Rankings/Included & Excluded WRs

• Wikipedia provided rankings for each event, sometimes indicating that the first record made was as 0 or WBT (World’s Best Time).

• WRs set that matched the previous record are counted and given .5 increment records.

  • In one instance, the same WR is matched four times and thus has rankings in the .25 increment.

• Rankings were redone considering the following:

  • Records set that should not be counted (due to doping violations, swimsuit violations, or records not being faster than the previous record) are marked NA and excluded from most analysis but kept in my dataset.

  • Records set in a yards pool (that are noted as such) are marked NA and excluded from analysis.

• Records set in the LZR Racer were included, even though the suit was later banned – an important part of swimming history!

Specific Races

• Adam Peaty’s 2014 WR was excluded in the Wikipedia dataset but I could not find any reason that it did not count – it was added back into the ranking.

• Glen Housman’s 1500 Free in 1989 was timed with a hand timer and removed from the rankings.

Data Cleaning

• Zoltan Halmay’s name sometimes had ` and sometimes not – these were standardized.

• The nationality was missing from all swimmers in the 400 Freestyle – information was filled in using a) nationality for that swimmer if they have a WR in another event and b) google search for documentation.

By Event: Notes and Other Background Information

• 50 Freestyle

  • Recognized by FINA starting in 1976.

• 100 Freestyle

  • Recognized starting in 1905

  • In the first four modern Olympic games, swimming competitions were held in open water (1896: Mediterranean Sea, 1900: Seine River, 1904: artificial lake, 1906: Mediterranean Sea).

  • In 1904 the Olympic freestyle race was measured in yards instead of meters.

• 400 Freestyle

  • Recognized starting in 1908.

• 800 Freestyle

  • The early records were done as 880-yeard freestyle races.

  • The 800 Meter Freestyle was recognized starting in 1931.

  • In more modern times, this was not included as an Olympic event for men until 2021 at the Tokyo Olympics.

• 1500 Freestyle

  • Recognized starting in 1908.

  • This was not included as an Olympic event for women until 2021 at the Tokyo Olympics.

• 50 of Stroke (Not Freestyle)

  • First recognized in the 1990s.

  • It was announced that the 2028 Olympics in LA will be the first Olympics to include the 50s of stroke.

  • World Championships and other meets have already included the 50s of stroke.

• 200 Backstroke

  • The regulations for the 200 Backstroke changed and were marked differently.

  • The later records are included, and the earlier ones are not.

  • Research and my own reading show that “early regulations” typically means the race was swum in a pool that was not regulation (or not in a pool at all).

• 100 Breaststroke

  • First recognized in 1961.

  • Women’s WRs first officially recognized in 1957.

• 200 Breaststroke

  • Before 1953, butterfly and breaststroke were largely the same stroke; various rule changes throughout the 1930s and then in the 1950s evolved the strokes into separate events with very specific rules for head placement, hand placement, and kicking.

  • First recognized as an event in 1908, with women in 1921.

• 100 Butterfly

  • Recognized in 1957.

• 200 Butterfly

  • Recognized in the 1950s.

• 200 Individual Medley (IM)

  • Men recognized in 1956, women in 1957.

• 400 IM

  • Men recognized in 1957, women in 1958.