Polarity in Causal Loop Diagrams
Posted: Sat Apr 08, 2006 1:45 pm
Posted by martin@utalca.cl
Hi,
I have a doubt concerning the definition of ""polarity"" in ""causal loop diagrams"". For instance, the ""+"" is in general said to mean ""when A rises, B will rise, too"" (or ""A decreases, so B, too""). This leads to strange situations like when thinking about population dynamics: ""when the <birthe rate> falls, <POPULATION> will decrease"" and someone protesting that the birth rate cannot make the population decrease.
I think the definition of polarity is ""when A rises, then B will have higher values than it would have had without the rise in A"" (and also the other way around). With this definition, there is no problem in saying ""<birthe rate> ->
POPULATION>"" with a ""-"" polarity: when the birth rate lowers, the
POPULATION>population
will be smaller than it would have been without the decline of the birth rate.
I find this ""dynamic"" interpretatino of polarity practical, but I've not seen it in the books and articles I've found so far (mainly by George Richardson and Kim Warren). So I'd be grateful if someone can point out a fault in my way of understanding polarity or indicate relevant literature.
Thanks,
Martin Schaffernicht
Facultad de Ciencias Empresqariales
Universidad de Talca
Talca - Chile
Posted by martin@utalca.cl
posting date Fri, 07 Apr 2006 08:12:23 -0400
Hi,
I have a doubt concerning the definition of ""polarity"" in ""causal loop diagrams"". For instance, the ""+"" is in general said to mean ""when A rises, B will rise, too"" (or ""A decreases, so B, too""). This leads to strange situations like when thinking about population dynamics: ""when the <birthe rate> falls, <POPULATION> will decrease"" and someone protesting that the birth rate cannot make the population decrease.
I think the definition of polarity is ""when A rises, then B will have higher values than it would have had without the rise in A"" (and also the other way around). With this definition, there is no problem in saying ""<birthe rate> ->
POPULATION>"" with a ""-"" polarity: when the birth rate lowers, the
POPULATION>population
will be smaller than it would have been without the decline of the birth rate.
I find this ""dynamic"" interpretatino of polarity practical, but I've not seen it in the books and articles I've found so far (mainly by George Richardson and Kim Warren). So I'd be grateful if someone can point out a fault in my way of understanding polarity or indicate relevant literature.
Thanks,
Martin Schaffernicht
Facultad de Ciencias Empresqariales
Universidad de Talca
Talca - Chile
Posted by martin@utalca.cl
posting date Fri, 07 Apr 2006 08:12:23 -0400