As mentioned above, typically it is not possible to measure as many as seven isotopic contrasts in a given neutron reflectometry dataset. The most common combination of isotopic contrasts that is measured in a dataset is tail-deuterated phospholipid in D 2 O and ACMW and fully hydrogenated phospholipid in D 2 O. Figure compares the relative evidence for each of the models when particular subsets of the available isotopic contrasts were analysis. The three datasets shown may be considered relatively common sets of experimental data containing one, three, and five isotopic contrasts.