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# Re: st: continuous data measured as ordinal catogories

 From Richard Williams To "statalist@hsphsun2.harvard.edu" , Stata List Subject Re: st: continuous data measured as ordinal catogories Date Thu, 08 Apr 2010 18:33:10 -0500

```At 05:05 PM 4/8/2010, Shehzad Ali wrote:
```
```Hi listers,

```
This question is probably beyond the scope of this list (so apologies in advance). I am dealing with an odd dataset in which willingness-to-pay has been measured using the following categories:
```
\$1 per month
\$5 per month
\$10 per month
Any other amount/month

```
I find this data very odd for the purpose of analysis (regression or other statistical methods). I want to model the relationship of willingness-to-pay and respondent characteristics. I wonder if someone on the list has any thoughts.
```
```
That last category is really weird. Does it include both less than \$1 and more than \$10? Do people maybe write in what the amount is?
```
```
If you want it as an independent variable, my first impulse is to break it into dummies. Also, Long & Freese's Regression Models for Categorical Dependent Variables Using Stata shows how to test whether it is legit to treat an ordinal independent variable as a continuous variable. See pp. 421-422. Basically, you run a model with the single variable treated as continuous, and then a model with the 3 dummies, and then test whether the 3 dummies approach provides a significantly better fit than the single variable approach. If not, then treat the var as continuous.
```
```
If you want it as a dependent variable, you could use mlogit -- or possibly one of the ordinal regression techniques if you think the last category always means more than \$10 (or less than \$1).
```

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Richard Williams, Notre Dame Dept of Sociology
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