The interplay of population and area creates a new collection of quadrants. The left axis depicts the population protected, from zero to more than 1 million, and the horizontal axis represents area, from 10 square miles to 100. If all 33,000 fire departments in the United States were plotted on this graph, we would see dots all over the place. This isn't the last word in level of service, however, because there's another variable to consider: value to be protected.

While people demand service, property is what's at risk. Therefore, the assessed valuation of a community is very often an indication of the community's ability to protect itself. Those communities that have an adequate tax base can afford a level of protection that may not be reflected by population and area alone. If you are fairly small and have a very low population, but you happen to live in a wealthy community, you may be able to afford something that someone down the street with exactly the same population and square mileage can't.

This may get a little tricky, but let's turn our four quadrants into a three-dimensional model by adding two more axes. On the vertical axis is assessed valuation, and on the horizontal axis is level of effort. Assessed valuation ranges from $1 million to more than $100 million, and level of effort ranges from $1 to $200.

Assessed valuation can be derived easily from assessor parcel information. Level of effort can be determined by looking at the amount of money that a community is willing to spend on its fire department on a per capita basis. Imagine two communities with an assessed valuation of $10 million each. In one community the residents decide to put $10 per capita into fire protection, and in the other they elect to contribute $100 per capita. You now have two different levels of service.

If we were to re-plot the nation's fire departments based on area, population, assessed valuation and level of effort, we would see a stratification of fire services that reflects the real world. In other words, this collection of axes is not so much a model as it is an expression of reality.

Now comes the tricky part, the balancing of too much and too little. We're entering the realm of public policy and the decisions made by those people who are elected to serve the interests of those being protected. At its simplest, the model works like this: If you have a lot to protect and you aren't willing to invest in fire protection, you might as well expect to loose some of it. If you're trying to protect everything and you can't afford it, you might as well expect to have system failure. The balance point is somewhere in between.