When an engineer makes a decision, from which car to buy to how long to stay at a relative’s house, he will do a benefit/cost (b/c) analysis. We have discussed this before on engineeringdaze.com.

We may also have mentioned the importance of the number 1, more precisely 1.0, to include the significant digit to the tenths. Today, we will emphasize this. We could take this to the hundredth or the thousandth or the millionth, but for most simple calculations, the tenths or hundredths will do. For now, we will keep to tenths.

What makes this number important to the engineer is that it is the tipping point, or the figurative line in the sand for the engineer when making a decision. If a b/c calculation results in a number greater than 1.0, then the activity is worth doing. Again, this can be from buying a roll of toilet paper to driving to the store for Tylenol because one of his kids “says” they have extreme pain from a baseball hitting their shin.

The difficult aspect about calculating a b/c ratio is that frequently either the benefit or cost is not easily quantifiable. If everything was given a monetary value, that would make life easy. But how do you measure the amount of whining of a kid with shin pain? How would one measure the annoyance level of spending time at the house of the relatives? How about the cost of sleeping on the couch rather than in bed if one decides not to buy flowers for an anniversary?

Fortunately, engineers are very creative when it comes to putting value on things. In highway safety engineering, we put a value on human life. If that is the case, and it is, then we certainly can place a value on the whining level of a kid with a hurt shin, or the pain level that kid supposedly is enduring. And when we place a value on the benefit and the cost, it is a simple matter to find the b/c ratio and decide, quite logically, that, say, maybe flowers aren’t waste of money.

It all has to do with 1.0 – is the b/c greater than or less than this. Life can be no simpler.