--Effectiveness
Webster's says, "causing or capable of causing a desired or decisive result".
To me, "effectiveness" is part hindsight, part "what if" a la alternate universes, part foresight.
The very definition of the term requires determining results, which means you have to evaluate your success after the fact. Thus hindsight. You have to look back and ask yourself, "well, I did X and I can now see what happened; did I get a desired/decisive result"?
The "what if" comes in in a qualitative sense. In order to do any sort of comparison, we have to imagine what would happen if all circumstances were the same but we did Y instead of X. One way to do that would be to go back to a saved game right before doing X. However, the random nature of the game will change the result, so it's probably better to simply admit that we can try different things and compare in a general way from game to game, but to some extent we will have to use judgement in doing a comparison to determine which strategy was most effective. In addition, we need to admit that there are always potential things we don't take into consideration. I see people all the time in Civ taking a small sample set (in a Statistical sense) and drawing conclusions. That doesn't mean the conclusion was wrong, but it means it is suspect. Let's admit that fact.
Foresight comes in from three things: past experience, our knowledge of game settings, and our knowledge of the way the game is programmed (from the manual and Civopedia if nothing else). Using these things, we make decisions. e.g., "I'd better start building up my military a bit, if I don't want Toku to attack." This is a guessing game, and is where good players distinguish themselves from mediocre players. (Note: your skill level has nothing to do with your enjoyment factor, nor should it.) In addition, this is determined in part by how well you did #1 hindsight and #2 what if from previous games.
--Strategy
Webster's says, "the science and art of conducting a military campaign in its large-scale and long-term aspects."
In Civ, everyone tacitly replaces "military campaign" with "Civ game", I'm sure we'll all agree.
So what's a strategy? What you build and when you build it, what improvements you do and when, what you do with your units, the techs you research and what order, what negotiations you do and when.
"Science" implies utilization of knowledge acquired by careful observation and deduction of laws which govern changes and conditions of Civ and of a particular Civ game.
"Art" implies utilization of imagination and creative skill.
A strategy is defined without consideration for the effectiveness of it. You choose between strategies based on your perception of effectiveness.
--Preference
Webster's says, "the right to choose" and "to like better"
By definition, this has nothing to do with the definitions of effectiveness and strategy.
It will affect your selection of a strategy, however, because strategy is defined in part by imagination and creativity, and of course you might choose a strategy simply because you prefer at that moment to "take the path less traveled".
I think in Civ that preference could also cover other things you might have control over in the game. Game settings, for example.
I think I might add another term:
-- Circumstances
Webster's says, "an essential fact or detail / the elements of a total situation" and "the particular elements affecting a situation"
This, to me, includes game settings, results of previously generated game "die rolls" (combats, barb spawning, forest/jungle growth), the map, the AI leaders selected, etc.
This can drastically affect effectiveness. Especially if one or more of the circumstances are not taken into account. An evaluation of Berserks, for example, on an archipelago map is not a complete/comprehensive evaluation unless you also include data from other map types.
Wodan
