This is a method for hypothesis generation, but is not a valid way to draw inferences.
The reason why scientists don't draw conclusion from single data points (analogies) is that you can come up with flawed conclusions as a result. The changes could be purely random, or due to some other explanation that wasn't thought of.
In order of reliability:
1. Do an experiment where an intervention is assigned at random, and scored by a method that is blind to the intervention (preferably on subjects who are blind to the intervention - but that is hard for some cases).
2. Observe historical data where there have been many instances of each of the variables under study, avoiding correlation between variables with things like time.
3. Use anecdotes.
The reason why scientists don't draw conclusion from single data points (analogies) is that you can come up with flawed conclusions as a result. The changes could be purely random, or due to some other explanation that wasn't thought of.
In order of reliability: 1. Do an experiment where an intervention is assigned at random, and scored by a method that is blind to the intervention (preferably on subjects who are blind to the intervention - but that is hard for some cases). 2. Observe historical data where there have been many instances of each of the variables under study, avoiding correlation between variables with things like time. 3. Use anecdotes.