The next step in the calculation of the MH statistic is to use data from the contingency table to obtain an odds ratio for the two groups on the item of interest at a particular "k" interval. This is expressed in terms of "p" and "q" where "p" represents the proportion correct and "q" the proportion incorrect for both the reference (R) and focal (F) groups. For the MH procedure, the obtained odds ratio is represented by α with possible value ranging from 0 to ∞. A α value of 1.0 indicates an absence of DIF and thus similar performance by both groups. Values greater than 1.0 suggest that the reference group outperformed or found the item less difficult than the focal group. On the other hand, if the obtained value is less than 1.0, this is an indication that the item was less difficult for the focal group. Using variables from the contingency table above, the calculation is as follows: