Compare methods

	Sport Participation Time-Budget Diary	Accelerometer Cut-Point Calibration
Field	Sport Leisure Studies	Sport Leisure Studies
Family	Process / pipeline	Regression model
Year of origin	1998	1998
Originator	Jonathan Gershuny & Oriel Sullivan (time-use diary methodology)	Patty S. Freedson, Edward Melanson & John Sirard; Kelly R. Evenson et al.
Type	Episode-level diary survey pipeline for sport and leisure participation	Calibration regression / ROC model mapping accelerometer counts to activity intensity
Seminal source	Gershuny, J., & Sullivan, O. (1998). The Sociological Uses of Time-use Diary Analysis. European Sociological Review, 14(1), 69-85.	Freedson, P. S., Melanson, E., & Sirard, J. (1998). Calibration of the Computer Science and Applications, Inc. accelerometer. Medicine and Science in Sports and Exercise, 30(5), 777-781.
Aliases	Sport Time-Use Diary, Leisure Time-Budget Survey, Sport Participation Diary Method, Episode Diary of Physical Activity	Activity Count Calibration, Intensity Threshold Derivation, Accelerometer MET Calibration, Cut-Point Derivation
Related	3	3
Summary	The sport participation time-budget diary measures how much sport and leisure people actually do by asking them to record their day as a sequence of time-stamped episodes rather than answering a single recall question. Building on the time-use diary tradition formalized by Jonathan Gershuny and Oriel Sullivan, the method treats a day as an exhaustive, non-overlapping chain of activities, each with a start and end time, a location, and a record of who else was present. Applied to sport and leisure, it captures not only the duration and frequency of exercise, training, and active or passive recreation, but also the social and spatial context in which they occur. Because every minute is accounted for, the diary yields population estimates of participation that are far less prone to the over-reporting and rounding that plague stylized 'how often do you exercise?' survey items.	Accelerometer cut-point calibration solves the central translation problem of objective physical-activity measurement: a wearable accelerometer outputs dimensionless 'counts,' but researchers and health guidelines speak in intensities — sedentary, light, moderate, vigorous. Calibration establishes the count thresholds that map the device's output onto those intensity categories. Patty Freedson, Edward Melanson, and John Sirard's 1998 study of the CSA (later ActiGraph) accelerometer set the template, regressing measured energy expenditure in METs on accelerometer counts during treadmill walking and running and solving the regression for the counts corresponding to moderate (3 METs) and vigorous (6 METs) activity. Later work, exemplified by Evenson and colleagues' 2008 calibration for children, increasingly used receiver-operating-characteristic (ROC) analysis to find the cut-point that best discriminates intensity categories. The result in both cases is a small set of count thresholds that turn raw accelerometer data into minutes of activity at each intensity.