Hi ,
There is a classical approach based on Don Kirkpatrick's model of four levels training evaluation .
The other approach is a practical approach to it .
My question to you would be to explore who and why is this question ? I am saying this as sometimes this question is asked as a context to reduce training spends . In case it is coming from an operations or business person , my advice check the context .
Training is supposed to ensure effectiveness of process and skills not result / guarantee output . Indian Army is the largest investor on training , they nevercalculate the ROI as at times the benefits are of notional hygiene . At times training ensures base level performance .
In case it isan HR Head's questio then it must be linked to quality of output such as how many leaders have been created , what is the improvement in sales conversions , How has the FTR improved etc. Pardon my being slightly lateral in my approach to this issue . Views welcome .
dd