Athletics abbreviations
The sports under the umbrella of athletics, particularly track and field, use a variety of statistics. In order to report that information efficiently, numerous abbreviations have grown to be common in the sport. Starting in 1948 by Bert Nelson and Cordner Nelson, "Track & Field News" became the leader in creating and defining abbreviations in this field. These abbreviations have also been adopted by, among others, World Athletics; the world governing body, various domestic governing bodies, the Association of Track and Field Statisticians, the Association of Road Racing Statisticians, the Associated Press, and the individual media outlets who receive  their reports. These abbreviations also appear in Wikipedia. Times and marks. Almost all races record a time. Evolving since experiments in the 1930s, to their official use at the 1968 Summer Olympics and official acceptance in 1977, fully automatic times have become common. As this evolution has occurred, the rare early times were specified as FAT times. As they are now commonplace, automatic times are now expressed using the hundredths of a second. Hand times (watches operated by human beings) are not regarded as accurate and thus are only accepted to the accuracy of a tenth of a second even  when the watch displays greater accuracy. If the mark was set before 1977, a converted time to the tenth was recorded for record purposes, because they did not have a system to compare between the timing methods. Frequently in those cases there is a mark to the 100th retained for that race. Over this period of evolution, some reports show hand times also followed with an "h" or "ht" to distinguish hand times. With two different timing methods came the inevitable desire to compare times. "Track and Field News" initiated adding .24 to hand times as a conversion factor. Many  electronic hand stopwatches display times to the hundredth. Frequently those readings are recorded, but are not accepted as valid (leading to confused results). Some low level meets have even hand timed runners and have switched places according to the time displayed on the stopwatch. All of this is, of course, wrong. Hand times are not accurate enough to be accepted for record purposes for short races. Human reaction time is not perfectly identical between different human beings. Hand times involve human beings reacting, pushing the stopwatch button when they see the smoke or hear the sound of the starting pistol , then reacting (possibly anticipating) the runner crossing the finish line. The proper procedure for converting hand times would be to round any hundredths up to the next higher even tenth of a second and then add the .24 to get a time for comparison purposes only. But many meets displayed the converted marks accurate to the hundredth making the results look like they were taken with fully automatic timing. In these cases, some meets have displayed a 4 or a 0 in the hundredths column for all races. When detected, reports of these times are followed by a "c" or  ' to indicate converted times. Road race times are only considered accurate to a full second. To distinguish a full second time with hours, from a minute time with hundredths of a second, colons are used to separate hours from minutes, and minutes from seconds. A period is used to separate seconds from hundredths of a second. Transponder timing is becoming more common. The RFID detection system times the transponder chip, usually located on a runner's shoe as opposed to the official timing of the torso. Accurate to a full second, this is not significant, but in breaking microscopic ties , the data does not correspond to timing rules. Most road races cannot fit all participants onto the start line. Depending on the size of the field, some athletes could be several city blocks away from the start line and in the large crowd, could take minutes to get across the line. Results frequently indicate two times, the "gun time" would be the official time from the firing of the starting pistol, but the mat time shows the time the shoe crossed a sensing mat at the start line to the time the shoe crossed the sensing mat at the  finish line. Occasionally, when breaking ties using photo finish, times are displayed to the thousandth of a second. These times to the thousandth are not used for record purposes but times to the thousandth can be used to break ties between adjacent heats. Rules specify if a tie is broken this way, that all heats involved are recorded with the same timing system. Records. Most records are subject to ratification by the governing body for that record. On the world level, that is World Athletics. Each body has their own procedure for ratifying the records: for example, USATF, the governing  body for the United States, only ratifies records once a year at their annual meeting at the beginning of December. Until a record is ratified, it is regarded as "Pending" which is sometimes indicated by a following P. When a U20 is added, it indicates an Under 20 record, which indicates an athlete under 20 years of age before a given calendar age. Otherwise, the athlete is considered senior. Bests. Some records are ratified or tracked, but they are not to the same standard of quality or accuracy as a record. The term is "bests." IAAF lists bests for the  Youth division and for road racing records such as the marathon. It also tracks athlete personal achievements as bests. A Y indicates Youth. A youth athlete has not reached or will not reach their 18th birthday in the calendar year of competition. Circumstances and conditions. For events where wind assistance is a factor (outdoor races 200 metres or less, long jump and triple jump), the wind reading is usually reported in metres per second or "m/s". Disqualifications. Athlete disqualifications often reference the IAAF rule number under which the athlete was disqualified. This is typically written in the format (false  start as example): DQ R162.7. Initialisms. Organising bodies. The various organizing bodies of the sport are abbreviated into alphabet soup. Events. Due to the large number of athletics events that are regularly contested, presentations of results and statistics often use abbreviations to refer to the events, rather than the full form.