_dta:
  1.  additional_changes set up by Jean Roth , jroth@nber.org , 9 Feb 2018

ndc:
  1.  The National Drug Code (NDC) serves as a universal product identifier for human
      drugs and biologics.
  2.  Each NDC must be reported as an 11-digit code unique to the manufacturer of the
      specific drug or product.

ndcdash:
  1.  The National Drug Code (NDC) serves as a universal product identifier for human
      drugs and biologics.
  2.  Each NDC must be reported as an 11-digit code unique to the manufacturer of the
      specific drug or product.

hcpcs:
  1.  HCPCS codes are used by Medicare and monitored by the CMS .
  2.  HCPCS Level II codes are assigned to every service a medical practitioner provides
  3.  to a Medicare patient including durable medical equipment, prosthetics and
      orthotics supplies.
  4.  These codes are an alpha character followed by four numbers.

ndc13:
  1.  The National Drug Code (NDC) serves as a universal product identifier for human
      drugs and biologics.
  2.  Each NDC must be reported as an 11-digit code unique to the manufacturer of the
      specific drug or product.

  obs:           251                          
 vars:             9                          9 Feb 2018 15:57
 size:        52,208                          (_dta has notes)
-----------------------------------------------------------------------------------------
              storage   display    value
variable name   type    format     label      variable label
-----------------------------------------------------------------------------------------
ndc             str11   %11s                * National Drug Code (NDC)
ndcdash         str13   %13s                * National Drug Code (NDC) with Dashes
hcpcs           str5    %9s                 * Healthcare Common Procedure Coding System
                                                (HCPCS)
change          str65   %65s                  Change
newvalue        str95   %95s                  New Value
fileyear        int     %9.0g                 Year Data File Source
filemonth       byte    %9.0g                 Month Data File Source
oldvalue        str3    %9s                   Old Value
ndc13           str13   %13s                * National Drug Code (NDC) with Dashes
                                            * indicated variables have notes
-----------------------------------------------------------------------------------------
Sorted by: ndc  hcpcs  change  newvalue