LN and NOLOG Subcommands (CASEPLOT command)

LN transforms the data using the natural logarithm (base e) of the variable and is used to remove varying amplitude over time. NOLOG indicates that the data should not be log transformed. NOLOG is the default.

  • If you specify LN on CASEPLOT, any differencing requested on that command will be done on the log-transformed variable.
  • There are no additional specifications on LN or NOLOG.
  • Only the last LN or NOLOG subcommand on a CASEPLOT command is executed.
  • If a natural log transformation is requested, any value less than or equal to zero is set to system-missing.
  • NOLOG is generally used with an APPLY subcommand to turn off a previous LN specification.

Example

CASEPLOT VARIABLES = TICKETS
  /LN.
  • In this example, TICKETS is transformed using the natural logarithm before plotting.