Posted by: wolf | January 14, 2008

Another example for poor path diagramming

Last week I wrote about “conscientiousness in the brain” and the (artificial) example

“sportiness → engine size → max.horsepower → max.speed”

which illustrates that arrows into a path diagram don’t have anything to do with causality.

Well, just some hours after that a student presented her research project on multimedia learning in physics, and she had the following real-life example of a poorly designed path diagram:

“gender → previous knowledge → motivation → effective use of learning strategies” etc.

This example is wrong in even more ways than the previous, artificial one: not only is gender a different kind of effect (e.g. you can’t manipulate it and it won’t change over time — usually), even worse is the lack of arrows from gender to the other constructs if one even decides to include it into the model as a causal effect. Consider the following statement: “Jane’s being a girl caused her to have less previous knowledge”. Of course, it might be argued that being a girl is on average causes exposure to stereotypes (“Girls aren’t good at physics, they should rather learn to knit and sew”) etc. etc., but then gender is only a distal effect and surely not directly related to previous knowledge. But if we accept gender as a distal effect, then there should also be an arrow to the other constructs: Surely the stereotype exposition would just as well lead to a general reduction of motivation, effective use of learning strategies etc.

P. S. Is that grammatically valid, “path diagramming”? Well, what I’m writing about isn’t really “valid”, so who cares.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Categories

%d bloggers like this: