Turn-based Strategy is the best solution (Score 1)

You should look for a game where you think that the type of person who would be a good "deskjob" strategist would also perform well at this game.

Business strategy won't rely as heavily upon quick decision making in situations where time is of the essence quite the same way that military strategy would. Business appropriate strategy relies much more heavily on patience, foreward planning, situation assessment, and resource conservation.

In "real world" situations, prudent business decisions aren't made in the heat of the moment. The issues are carefully contemplated and examined from all angles because the benefits of careful planning and evaluation greatly outweigh the risks of spending time on them.

In real time games, stopping to contemplate the situation or to plan a complicated strategy can be fatal if done while the game is in progress. Creative and briliant strategies in such games can only be properly composed outside of the game itself, or while practicing in game sessions that "don't count." This could make it difficult to design a testing structure based on such a real-time game as Starcraft or Quake. You would be obligated to give your participants a period of practice time where they could plan their strategies outside of the gameplay that "counts." I'm sure you can see the hassle this could create. Placing time limitations for practice would upset the planning of any participants who may still be experimenting when time is called. It also presents situations that could spoil the scientificity of the results.

This is why I suggest that you opt for a turn-based strategy game for conducting your tests. A turn based game such as Civilization would be optimal for your testing purposes for the following reasons:

• Easy learning curve. Most turn based strategy games have simple enough interfaces that they can be completely explained by an in-game tutorial. There are no special nuances of a real time engine to learn on one's own. No time is spent learning how to put platoons of Zerglings into control groups, how to switch between control groups, or how to do it effectively(the hardest part).
• By removing the risk of being attacked while contemplating a course of action, the participants will be free to evaluate situations, plan extensively for long term campaigns, and micro-manage to their heart's content. Now the player's own, patience, dilligence, and attention to detail become the primary limiting factors to proper indepth strategic planning.
• When research brings them new units, technologies, political systems, and buildings, they will be free to read the descriptions and specifications of each one before deciding what to do with the knew knowledge. In RTS games, you commonly have to leave the game and look online or in a manual before you'll ever know whether a unit is worth producing. Otherwise, you have to devote the resources in-game to create one of the structures or units before you'll ever know what it does. In turn based strategy games, the information is right there in the technology tree. One never has to leave the game to get the necessary information.
• In real time games like Quake and Starcraft, player traits such as reaction time, 3D spacial coordination, and composure under stress are much more important early on than strategic thinking. In turn based strategy games, the strategic ablitities of new players will be apparent much earlier in the game than in real-time games.
• It may be easier to find people who haven't played a turn based strategy game, since RTS games have been in public favor for so long.

That about wraps it up. If you think my points are well grounded, I also have some ideas about implementation.