This column is about a way to understand and describe certain mathematical relationships: exponential functions expressible with logarithms. Think of a trend line on a scattergram as a visual math function. The equation for it that Excel produces is a function – a mathematical connection that links one number to a second number in an orderly and specific manner. There can be many functional relationships, including linear and exponential, the latter showing the familiar hockey stick of increases seen with population growth and power laws.
With a linear function, the numbers change in lockstep: one more year of practice and $10,000 more in bonus. One more law firm retained; one more matter opened in a database.