Table 1.

Risk of individual study bias questions and rating explanations.

	Rating Explanations
Bias	Low Risk (3 Points)	Medium Risk (2 Points)	High Risk (1 Point)
Sample	Sample is a group of athletes, in the sport; performance is score, outcome of that sport.	Sample is like the high category, but sport outcome is like the low category or vice versa.	Sample includes recreational athletes, but not in a realistic sport context, and/or performance is based on assessment of a skill rather than a game statistic or sport outcome.
Random selection	Stated random selection occurred from a much larger group (e.g., from all athletes at an event).	Random selection occurred within a group of athletes (e.g., college team at an event).	No random selection of any kind stated.
Nonresponse	Appears most participants completed the measures.	Some non response occurred.	Seems most did not do it, e.g., a big race, subjects recruited at the race, most likely most did not do it.
Direct collection	Yes, all in person.	A mix of online and in person.	All online or mail.
Confidence measure	Study level reliability presented.	Valid and reliable measure (e.g., all except the 1-item measure) but study level reliability not presented.	Made up confidence measure.
Sport measure	Event time, win–loss, outcome, golf score, judge rated (gymnastics).	Participant statistics.	Self or other rated subjective, or vague (good vs. bad performers), team selection.
Data collection	Yes, all the same.	No option for a medium rating.	A mix of ways (e.g., individual for some, in large groups of others).
Anonymity	Yes, stated.	Participants presented informed consent.	Not stated in methodology.
Time	≤15 min	16–60 min	>1 h