In trying to change people’s behavior when it comes to personal finance, I have come to believe that it is not so much for the lack of “great posts” or wonderful insights as much as it is a question about the right person reading the right post at the right moment in time.

In exobiology there’s an equation used to estimate the number the advanced civilizations in the galaxy. (Our galaxy is the only one of relevance… the nearest other galaxy is 2 billion light years away. In between galaxies, there’s mostly a whole lot of “empty” which excludes hopping from star system to star system.) It goes like this:

Multiply the rate of star formation per year in the galaxy (large!) by the average number of planets per star (0-15 or so) multiplied by the fraction of those which can support life (?) multiplied by the fraction of those which will develop life (?) multiplied by the fraction of those where life is intelligent (?) multiplied by the fraction of which develop an advanced civilization emitting signals (we do) multiplied by the number of years such an advanced civilization lasts (300-1000 years?).

It may easily be that such a number decreases rapidly due to low probabilities.

For blogging, the odds of a “conversion” can be written in a similar fashion, namely

Multiply the rate of people becoming interested in personal finance by the fraction of people on the internet multiplied by the fraction of those who read blogs multiplied by the fraction of people who is reading a particular blog multiplied by the number of posts multiplied by the fraction of posts the person has read multiplied by the fraction of posts the person is in a frame of mind to accept the message in given post multiplied by the numbers of months such a person stick around reading the same blog.

From such a perspective, it’s interesting to note that most factors are actually out of my hands. The only two variables I control or influence to some degree are


  • The fraction of people reading a particular blog.
  • The number of posts.

I can influence the first variable by advertising on other blogs, guest posting, and participating in carnivals. I can control the latter by writing more posts.

Of those two, I have clearly done more writing than advertising. I note that advertising can also be indirectly influenced by writing good posts are relying on word of mouth from “the mouths of others rather than your own”. This seems to be a quality condition rather than a quantity condition though—the equation be easily be expanded to include those factors.

In both cases, the equations can be used to fully realize just how many variables enter the equation. More importantly, it provides an alternative way of framing the question: What makes someone make a decision based on something they just read?