There are two dominant fleet doctrines in Astro Empires: Balanced and Efficient. The primary one is balanced, which mandates a balanced ratio of each unit in the fleet. The Efficient Doctrine is similar, but it looks at the relative efficiency of units in suggesting which units to add to your fleets. Ironically, the Efficient Fleet Doctrine demurs in the use of capital ships; much like the French Small Fleet Doctrine. Therefore, this guide honors the naval heritage of a doctrine that advocates for more efficient, smaller units and labels it the Small Fleet Doctrine.

At its core, AE is still a rock-paper-scissors game. Unit efficiency is relative to the units used by your rival. Efficiency is an economic term that describes a condition without waste. So, a more-efficient fleet is one that produces less economic waste. The objective is to cause the most damage to your opponent for the least cost—cost-efficiency. This guide, therefore, discusses the different units and their relative efficiency to one another, and how to develop an efficient fleet. The first section discusses the role of each fleet unit. The second section touches on base defense structures. The third section discusses implementation of the Small Fleet Doctrine.

http://espacesociety.org/AstroEmpires/S ... etDoctrine

That is well worth reading.