Extracting random (every 50 to 100 intervals) retail companies from 2007 - 2009 (prior to Dot Com Bubble) 
Posted: 21 September 2014 05:17 PM   [ Ignore ]
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Hi,

I want to test 50 randomly selected retail companies considered to have had overvalued stock prices prior to the dot com bubble burst (2007 - 2009) .  So I need to extract at least 3,000 retail companies, calculate Tobin’s q, and then randomly select 50.  But I think doing a query for 3,000 companies, its market cap value, book value of debt, and BV of assets is too large for the query yes? 

I then need to repeat this for the period of 2009 thru 2013.  What is the best way to do this in wrds?  Thank you.

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Posted: 21 September 2014 06:24 PM   [ Ignore ]   [ # 1 ]
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hi Kelliot,

I would download all retail firms in Compustat (I am assuming you will be sampling US firms) over the period you will be sampling. I doubt there are 3,000 retail firms though, but if there are, it is not an issue.

Compute a random variable for each firm-year, and then sort on this variable, and take the first 50 (or however many you need).

This can be done in Excel/SAS/etc.

best regards,

Joost

 

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Posted: 22 September 2014 11:09 AM   [ Ignore ]   [ # 2 ]
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Thank you.  I was able to pull them by SIC codes.  One more question:  Is there a file defining all the various abbreviations in the query results?  For example, I requested accounting system and it returned a DS column.  Is that the abbreviation for “Double-entry system” or ?  Thanks again.  I am truly impressed by the people who oversee this system.  Have a good day.

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Posted: 22 September 2014 09:12 PM   [ Ignore ]   [ # 3 ]
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you’re welcome smile

On wrds’ website go to ‘support’, ‘dataset list’, and select the library/dataset you are using - this will take you to a page with (one-line) descriptions of each variable. For more in-depth information, use the manuals of the vendors. (Links to vendor manuals are displayed in the web interface where you select/download data).

best regards,

Joost

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