Method of evaluating a golf club

A method of evaluating a golf club comprising the steps of:

• a step (St1) of using at least one computer for determining motions of the golf club during a swinging motion of a golf player including a period ranging from a time (Ts) to a time (Tf);
• a step (St2) of using the at least one computer for obtaining power index values (Pw) in a time series during the period ranging from the time (Ts) to the time (Tf), based on the result of the determination;
• a step (St3) of using the at least one computer for obtaining a power integration value (Sp) by integrating the power index values (Pw) during the period ranging from the time (Ts) to the time (Tf);
• a step (St4) of using the at least one computer for calculating club energy (Eg) of the golf club at the time (Tf);
• and
• a step (St5) of using the at least one computer for quantitatively evaluating club suitability based on the power integration value (Sp) and the club energy (Eg);
• wherein each of the power index values (Pw) is a value which is correlated to power of a work provided from the golf player to the golf club;
• and wherein the club suitability is evaluated based on a ratio (Sp/Eg) of the power integration value (Sp) relative to the club energy (Eg).