Follow-up to piecewise regression question

Posted by parisec on
URL: http://spssx-discussion.165.s1.nabble.com/Follow-up-to-piecewise-regression-question-tp5668949.html

Hi all,

 

I posted a question last week about extending the information from these articles:

 

http://www.ats.ucla.edu/stat/spss/faq/piecewise.htm

 

http://www.spsstools.net/Syntax/RegressionRepeatedMeasure/PiecewiseRegression.txt

 

.....to accomodate having the coefficient represent the increase in odds of an event for every 1 year increase in age within an age group.

 

The examples in these articles demonstrate how to compute this when you want to split a group into above or below a single value such as <14 and 14+. I think that to have multiple groups, i need to constrain the age group so that the lower limit of the age group is 0 and each year in age within the age group increases by 1. The end result is that the number of cases in the new age matches the number of cases in the 38-50 age group.

 

With this in mind, i computed below what I think is the correct new variable to enter in a piecewise regression for a 38-50 age group.

 

However, I cannot find an example that validates or invaldates this idea.

 

Thanks for any references or information you may have.

 

Carol

 

 

 

age	piecewise age 38-50
27	.
28	.
29	.
30	.
31	.
32	.
33	.
34	.
35	.
36	.
37	.
38	0
39	1
40	2
41	3
42	4
43	5
44	6
45	7
46	8
47	9
48	10
49	11
50	12
51	.
52	.
53	.
54	.
55	.
56	.
57	.