Much of my work is related to understanding how statistical patterns are generated. One of the most important concepts is the propensity-selection-threshold. Propensity is a measure of the tendency or probability for an individual to react to the environment in some way. Selection is the specific situation that results in some event occurring. Threshold is the statistical point at which the average propensities intersect with the average selections.
The only place I have seen some of this discussed is in the criminological literature. Adolphe Quetelet discusses the propensity for crime in his works. De Candole and Durkheim talk about the importance of the selection processes in determining crime rates. Quetelet discusses a “crime budget” in his work. He notes that crime rates are very stable from year to year. In my work on the age crime curve, I found that this stable point is best conceptualized as a threshold.
I suppose that I might as well start with studies in criminology in studying how living organisms function. One can find a wealth of crime statistics to study. I was able to get crime statistics from the FBI for my work on the age crime curve. The work on the age-crime curve has some of the best visual representations of the propensity-selection-threshold model.
Propensity
Quetelet’s work spanned a number of areas. He was interested in crime statistics and was one of the first crime statisticians. France started collecting national and regional crime statistics in 1925. In analyzing the crime data from France, Quetelet discovered the ‘age-crime curve’ and the “crime budget.” Quetelet developed the idea of a “propensity” for crime, which was included in the title of his work on the age-crime curve (Translated as “Adolphe Quetelet’s Work on the Propensity for Crime at Different Ages“). He also did some studies involving the measurement of physical characteristics and discovered that physical traits tended to be normally distributed. Quetelet was interested in the application of statistics, which had generally benn confined to the physical sciences. He tried to develop a “Social Physics” in order to try to utilize the physical concepts in the study of social phenomena. He described a concept called “the average man” as a basis for research.