This method is influenced by assumption that at time zero of a planet, the surface had no craters and the craters which followed time zero are spatially and temporally random. It can only be applied with accuracy to planets which have little to no tectonic activity, since constant resurfacing (like on Earth) would distort the true number of craters over time.
The method assumes that at the beginning of a planet's history, it had no craters on its surface and subsequent craters were randomly placed in both space and time. It can be applied accurately only to planets with little tectonic activity, as continuous resurfacing would otherwise misrepresent the true number of craters over time.