Convert data from quarterly data to monthly data for multiple companies?

[mmmark]

I'm searching for a way to convert quarterly data:

Here's a sample. I have about 150 companies with quarterly data from 2002-2012.

Ticker          date               Price    

AAA         2002/03/31          100

AAA         2002/06/30          125

AAA         2002/09/30          100

AAA         2002/12/31          100

AAA         2003/03/31          102

....

AAA          2012/12/31          95

ABB         2002/03/31          100

ABB         2002/06/30          125

ABB         2002/09/30          110

ABB         2002/12/31          100

ABB         2003/03/31          102

....

ABB          2012/12/31          99

The two problems I'm facing are

1. How to incorporate the ticker, and the fact that we're extrapolating/expanding for mutliple companies.

2. The dates are quarterly end, rather than at the start.

How can I expand this data to monthly or even daily?

[PGStats]

If you have SAS/ETS licensed, PROC EXPAND does exactly that. - PG

[mmmark]

The two problems I'm facing are

1. How to incorporate the ticker, and the fact that we're extrapolating/expanding for mutliple companies.

2. The dates are quarterly end, rather than at the start.

I have SAS basic and EG.

[mmmark]

Since the ID statement cannot handle anything other than a date value and you can't have one date appear more than once (which each date does for each company), how can I repeat the PROC EXPAND process for each company?

[mmmark]

Right now what I can think of is perhaps creating a separate dataset for each company, apply PROC EXPAND, then combine the datasets. This would involve hundreds of datasets however....

[mmmark · Accepted solution]

Just figured it out, it was the simplest thing!

A BY statement can be used with PROC EXPAND to obtain separate analyses on observations in groups defined by the BY variables. The input data set must be sorted by the BY variables and be sorted by the ID variable within each BY group.

Use a BY statement when you want to interpolate or convert time series within levels of a cross-sectional variable. For example, suppose you have a data set STATE containing annual estimates of average disposable personal income per capita (DPI) by state and you want quarterly estimates by state. These statements convert the DPI series within each state:

   proc sort data=state;

      by state date;

   run;

   proc expand data=state out=stateqtr from=year to=qtr;

      convert dpi;

      by state;

      id date;

   run;

[PGStats]

Great! You should be able to answer your initial request now. - PG