Discussion #1 - Tell us about a "causal study" you've been involved in.

In the week #1 reading there is a description of a "causal study".  In your own words, relate an experience you've had at work, home or other activity where you have participated in a causal study.  While we don't normally think in those terms, these types of investigations are very common.  Please describe the variables in the situation (there can be more than 2) and summarize your thoughts about how a problem was solved or a situation was changed using this basic research method.

There are no references needed for this discussion.  Feel free to use other sources to supplement your understanding but I want to see your thoughts, ideas and conclusions in the post.