Economic historians who study the medieval or Ottoman Middle East or any point prior to the twentieth century have been unable to make long-term comparisons of quantitative data from land surveys – and for a very good reason. A quantitative comparison of this nature is impossible because it amounts, as the saying goes to “the comparison of apples and oranges.” A primary example of this problem is trying to compare two of the most important land surveys of Egypt spaced several centuries apart: al-Nasir Muhammad's (r. 1310-41) cadastral survey (al-Rawk al-Nasir) in 1315 and Muhammad Ali’s (r. 1805-1849) cadastral survey in 1814. As they stand, it would seem clear that these two surveys cannot be compared. Over the intervening five centuries, not only did the methods for conducting surveys change but also the methods for classifying land and the units of measurements. In addition, units of currency or the valuation of output had changed. An additional complication is that rural villages had either moved or disappeared between these two periods. Studying long term changes between these two surveys can’t be done using linear comparisons. So we propose a new method for grappling with comparisons of this sort. Systems Ratio Analysis compares these apples (1315 CE cadastral data) with those oranges (1814 CE cadastral data) by comparing separately (set a1) 1315 data with (set a2) 1315 data and (set b1) 1814 data with (set b2) 1814 data. We will show how, given certain specific preconditions, the problem can be solved by calculating the relative ratio between ratios (a1/a2) (b1/b2). Very effective comparisons across periods of time (longer than 500 years) can be made. We provide proof of our method in this discussion by analyzing and comparing results from the 1315 and 1814 survey using Systems Ratio Analysis.