interpolating 100+ variables

[putteringpluie]

I have census data from 2001 and 2011. I want to interpolate all the variables for the in-between years by simple linear function. I don't want to use proc expand because of its constraint that slope will be zero in the beginning and end values. Any suggestions?

  proc expand data=have out=want;
      by state;
      id year;
   run;

[Reeza · Accepted solution]

PROC REG or a linear regression type models? That's still going to be a hell of a lot of variables and the assumption of constant growth isn't correct either. 

[putteringpluie]

Thank you for such a quick reply. I was wrong about the assumptions in proc expand. The slope need not be zero. 

[Reeza]

PROC TIMESERIES will also fill in missing time with several options. 

[ballardw]

---

@putteringpluie wrote:

I have census data from 2001 and 2011. I want to interpolate all the variables for the in-between years by simple linear function. I don't want to use proc expand because of its constraint that slope will be zero in the beginning and end values. Any suggestions?

---

If this is US Census bureau data I would recommend using the annual estimates that are available. I doubt if anything the Census works with actually has an 11-year straight line trend except the year variable.