Firstly , you need to address which type of productivity you want to measure : factor, partial or total productivity . Then , identify the hard and soft factors that affect productivity in construction industry . Soft factors are certainly important and worth attempting in a construction industry . Lastly . computation of productivity indices involves rationalising the units into common metrics. 

Many thanks Aloysius. Your help is meaningful to me.

It is important to carry out thorough literature review after defining the problem of the research; then only research framework may be established.

Many thanks Sanjay.