By using the Kelly Grid method it is possible to obtain insight in the  dimensions that are important in the perception of the respondent when  looking at a market. A triad is selected at random from several products which are representatives of a market. The respondent is asked 'in  which way two of these items differ from the third one. This is  evaluated in-depth for the triad. Then (again at random) another triad  is selected and the process is repeated until no other dimensions come  up.