operations of war. It will be noted that it is the marginal profitability, i.e. the gain resulting from small increases in some factor, that is given directly by such analysis. He also notes elsewhere that Csome parts of modern economics seem to use a variational technique closely analogous to that described in the second (i.e. the paper dealing inter alia with the convoy analysis). Taking all the circumstances into account, it seems fair to conclude that the Admiralty team's choice of criterion for their investigation was correct. Appreciating the urgency of the situation, and being aware of the limitations of the data available to them, they did not seek to use over-sophisticated methods or achieve spuriously precise results. They dealt with the problem analytically at the level at which analysis was feasible, and they left to judgment and common sense the consideration of those factors which could not be handled analytically at the time.