It occurred to me recently that I frequently write and speak about the concept of testing, but have not really shown the steps of how to create random groups. Establishing random groups is an essential component to an effective AB testing or multivariate testing strategy. Assigning test subjects, in this case, potential survey respondents, to groups in a random fashion minimizes the potential for bias in the test.<\/p>\n\n\n\n
Why is this important? The scientific method relies on the ability to control for the variance. Randomization is the best tool we have for minimizing the effect of factors that are outside of our control. Employing randomization in AB testing allows us to keep our focus on the test elements and not worry about whether or not a survey participant has lost their job, as an example of an extraneous factor.<\/p>\n\n\n\n
In creating test groups I employ both MS Excel and SPSS, although the work could be done entirely in SPSS or any other survey data analysis package. \u2018Order\u2019 is one of the main threats to creating valid test groups. Often we do not know how, or if a list is ordered. Examples might be alphabetical ordering by last name or account number, newest customers\u2019 first, geographic region, etc. In this case creating a bit of randomness is a good thing. If your list is in Excel add a column and use the random function. This creates a random number for each record. This random number can then be sorted, either ascending or descending. If there was order present in the initial list it will now be randomized out.<\/p>\n\n\n\n\t