  Uplift, essentially being the difference between two probabilities, is a
central number in marketing performance measurement. A frequent question in
applications is whether the uplifts of two campaigns are significantly
different. In this article we present a new $\chi^2$-statistic which allows to
answer this question by performing a statistical test. We show that this
statistic is asymptotically $\chi^2$-distributed and demonstrate its
application in a real life example. By running simulations with this new and
alternative approaches, we find our suggested test to exhibit a better decisive
power.
