Checking database coverage (companies)
As research students begin to scope their dissertation projects, they often ask about the availability of company data for a specific market (country). Two basic questions are how many companies are covered by a database, and how much historical data is available.
This post will take South Africa and Datastream as a concrete example, but it can be adapted to other databases.
Using Thomson Reuters Datastream Navigator Critera Search we can search for :-
- Market equals South Africa
- Major Security is Yes and Primary Quote is Yes (to ensure that there is only one equity series for a company)
- Status is All (to include both active and dead/inactive companies)
This search returned 1295 results, and on the Base Date header we can select the results to be oldest to newest
A total of 1295 is a reasonable number of companies, and the results show that data is available from January 1 1973.
This list can be downloaded for further analysis using the Excel icon at the top right.
One of the columns in the Datastream Navigator output, WS, indicates whether the company is in Worldscope, and therefore whether company accounts information is available.
The summary statistics for WS and Equity Status are
|in Worldscope||Not in Worldscope|
The Datastream Base Date (BDATE) variable gives the first date for which price data is available for a company (equity series). There is a Worldscope variable WC11516, Date added to product, but when a company is added this can include historical accounts data. For example, the company AECI (dscode 930060) has a value for WC11516 of 19920609 indicating it was added to Worldscope in June 1992. However a time series request for net sales (WC01001) shows that data is available at least from 1980.
Creating a Datastream list and then doing a few test requests is the quickest way to check the availability of specific data items. See our guide Datastream Part 2 (List Creation) for more details.
Datastream covers approximately 1300 South African companies, about 400 of which are active (on May 28 2014), and price data goes back to 1973. Company accounts data is available for approx 850 of these 1300 companies, and data pre-1990 looks limited.
A quick equity screen on Thomson ONE.com has 324 active South African companies (386 if active/inactive is selected). (This is what we would expect – dead companies are removed from Thomson ONE.com as they are no longer of interest to professional investors.)