The results suggest that the Champdas Master system can be used validly and reliably to gather live football match statistics by well-trained operators.

The intra-class correlation coefficients and typical errors ranged from 0.90 to 1.00 and ranged from 0.01 to 0.24 for two independent operators within two data collections. The Kappa values for the inter-operator reliability of were 0.97 and 0.89. The high Kappa values (Operator 1: 0.92, 0.90 Operator 2: 0.91, 0.88), high intra-class correlation coefficients (varied from 0.93 to 1.00), and low typical errors (varied from 0.01 to 0.34) between the first and second data collection represented a high level of intra-operator reliability. The Aiken’s V averaged at 0.84 ± 0.03 and 0.85 ± 0.03 for the validation of indicators. Four well-trained operators divided into two groups that independently analyzed a match of Spanish La Liga. Twenty professional football coaches voluntarily participated in the validation of match variables used in the System. The aim of the present study was to investigate the validity of match variables and the reliability of Champdas Master System used by trained operators in live association football match. 3AI Sports Engineering Lab, School of Sports Engineering, Beijing Sport University, Beijing, China.2Facultad de Ciencias de la Actividad Física y del Deporte, Universidad Politécnica de Madrid, Madrid, Spain.1China Football College, Beijing Sport University, Beijing, China.Bingnan Gong 1,2, Yixiong Cui 3*, Yang Gai 2, Qing Yi 2 and Miguel-Ángel Gómez 2

Definition of validity and reliability