While this method is simple, it is not very accurate. In particular, there is a tendency to overestimate the amount of C2S and underestimate the amount of C3S. One study found that the Bogue calculation gave C3S contents that were on average 8% lower than of those obtained from light microscopy (a technique that is reasonably accurate for estimating C3S). Also, the sum of the four minerals tends to be much less than 100%.