Interpolating with Proc Expand

[SAShole]

Hi SAS Friends,

I have a dataset with yearly household change from 2004 to 2013 by county. I want to interpolate the data into quarterly data. any suggestions on which method (spline,notaknot, natural, slope, step, aggregate, join etc.) to use?

a colleague also suggested that i could solve this using Proc Mixed. He indicated that i could run a regression for each county and get the slope and intercept. any ideas how to do that?

Thank you for your help,

sample data:

data sample;

  input county $5. COUNTY_NAME $18. ref_year $6. YoY_Chg best12.;

  cards;

01001 Autauga County c0405 0.0231

01001 Autauga County c0506 0.0299

01001 Autauga County c0607 0.0284

01001 Autauga County c0708 0.0295

01001 Autauga County c0809 0.0013

01001 Autauga County c0910 0.0022

01001 Autauga County c1011 0.0173

01001 Autauga County c1112 0.0494

01001 Autauga County c1213 0.0002

01001 Autauga County c1314 -0.0024

01003 Baldwin County c0405 0.0334

01003 Baldwin County c0506 0.0451

01003 Baldwin County c0607 0.0439

01003 Baldwin County c0708 0.0589

01003 Baldwin County c0809 -0.0038

01003 Baldwin County c0910 0.0068

01003 Baldwin County c1011 0.0383

01003 Baldwin County c1112 0.0147

01003 Baldwin County c1213 0.0082

01003 Baldwin County c1314 0.0253

;

run;