Deciles and re-scale variables

[Helen Chang]

Hi,

Does anyone know how to first rank firms into deciles based on a certain variable and re-scale them to range between zero and one?

Thanks!!

[Clyde Schechter]

If you are doing these deciles within some grouping of firms (say an industry, or certain years) then you can either install the -egenmore- package from SSC and use -by grouping_variable: egen decile = xtile(certain_variable), nq(10)-, or you can install -runby- and write a little program that uses the -xtile- command to calculate the deciles in a single group, and then -runby- that program -by(grouping_variable)-.

If this is just an overall calculatoin of deciles for the entire data set, with no grouping variables, then the -xtile- command by itself will suffice.

To re-scale them to range between 0 and 1,

gen scaled_decile = (decile-1)/9

[Helen Chang]

Thank you very much!! It works perfectly

[Attaullah Shah]

For deciles over a grouping variable, you can use astile (from SSC). Unlike Stata's official xtile, astile is byable. astile handles by-group calculations super efficiently. For example, the difference in time when used with bys and without bys is usually a few seconds in a million observations and 1000 groups.

* Download from SSC

ssc instll astile

help astile

* An example of deciles over groups
* Download example dataset

    . webuse grunfeld
 
* create 10 groups of firms based on their market value in each year 
 
bys year: astile size10=mvalue, nq(10)