Since the first wargames, the capabilities of units have been expressed in terms of Movement Allowances and Combat Strengths.

The Movement Allowance

The Movement Allowance is a strange concept, because it assumes a unit moves at a constant rate. This is a necessary abstraction. How do we go about assessing this?

An example comes from Napoleon at Bay: Napoleon had a set of dividers set at twenty miles on his map scale, and that was the distance that he normally expected a force to move. However, there were instances in 1814 where forces moved as far as 36 miles in one day. The normal march schedule allowed every marching unit to have a five-minute break every hour, the halt for pipes-smoke break.

After four hours there would be an hour break. Normally the troops would only march eight hours per day. Of course they could march 12 or even more hours in a day in a forced march situation.

I made 20 miles the normal march of units in the game-a Movement Allowance of 5 for infantry. To allow for a much quicker march I added the Forced March Segment.

The mobility of forces really didn't change much from 1814 up to 1940, as it was based on the limits on a walking man loaded down with pack, equipment and arms, sharing the road with crowds of people. There's a lot of waiting time involved, and if there are any obstructions in the road this can cause a bottleneck for the whole army.

The Movement Allowance is the easiest factor to determine because it is based upon a physical ability. You can even check it yourself. I used to live near the reservoir in Central Park, with a jogging trail around it, partly paved with gravel. To get an idea of the impact of weather, I would go out and walk that path in frost, in snow, in clear weather, in mud, test the consistency, and use my own judgment and imagination to assess the phenomenon I was trying to portray in the game.

The movement rates of infantry forces were checked against statistics on the marches of troops, until I was satisfied that historical rates of march were possible in the game. This is the criterion against which the success of your game has to be measured. Is the historical performance possible?

After you've made your map and counters, and you've decided on a basic Movement Allowance and turn scale that seems to fit, the next thing is to set your game up historically, and push the pieces through their historical paces turn by turn according to the best sources you can find.

The criterion against which the success of your game has to be measured: Is the historical performance possible?

Particularly of interest are marches that were lightly opposed by the enemy, if opposed at all. You want to see a march by a force moving its 'Maximum MA' each turn for several turns.

This concept of the Movement Allowance is an artificial but necessary construct because it doesn't represent any objective reality. It is simply the best judgment of military theorists who figured out that a 20-mile march was very achievable. Nonetheless, troops often did not manage to achieve their assigned destinations, even when they were unopposed.

The Combat Strength

It's even more difficult to determine combat strengths. There is the pragmatic approach-try some numbers based on a seat of the pants judgment, and check your results and adjust the strengths until you seem to have it right. That's the trial and error method, and I suppose it can work, but I prefer a more objective evaluation. However, the objective approach can also be very tricky.

The designer of Air Force -- Craig Taylor (one of the very best) assigned the firepower ratings of the various aircraft according to the weight of shell fired by the main armament of each aircraft. The larger the calibre of the gun, the higher the combat value of the aircraft.

Is the sheer weight of the shell enough of an indicator? There are many other factors that play into the effectiveness of fire besides raw weight. However, as a pragmatic matter this method had the virtue of ease of development (there were a lot of aircraft to be evaluated). The problem was that generally, the higher calibre guns fired fewer rounds within a given period.

Some aircraft in the game, in particular the B-17, were way too powerful. So when we redesigned the game (at Avalon Hill in 1980) we re-evaluated the firepower numbers of all the aircraft based upon the weight of shells delivered over the duration of a turn, and came up with a very different number.

When designing NAB (in 1977), I decided to avoid any subjective evaluation and make 1,000 men a strength point, regardless of nationality or quality of troops. That was a pretty radical idea, and certainly there has been some criticism of that method. However, with unweighted numbers, it's up to the game design to bring out the reasons why the Imperial Guard, for instance, is more valuable than Russian line troops. The Guard suffers no attrition, and can thus move around more quickly, fight in more battles, and at a higher strength than Russian line troops. This brings out their qualitative advantage in another way than just giving them a higher combat value.

With the 1997 edition we added the Combat Effectiveness option, assigning ratings, again subjective ones, showing how a unit might lose effectiveness and be unable to attack. Rather than just reducing its combat strength, this brings out in another way the qualitative differences of units.

Among the hard-pressed designers at SPI facing complex issues such as attrition and morale, the joke used to be "Well, just build it into the combat strength." Once we decided we were not going to build things into the combat strength anymore, our games began to develop in unforeseen and original ways.

Design Symposium

The Evaluation of Units
What is Wargame Design?
The Subsystem