Convert R and S-Plus factors
Both R and S-plus have a type known as a "factor". This consists of an ordered set of zero-based numbers [0…n] with a corresponding set of alphanumeric labels. For instance, a factor representing "yes" and "no" survey responses could be represented by a vector of zeros and ones and a vector of strings "yes" and "no" where 0= "yes" and 1 = "no".
Since factors have no direct analog in other statistical systems, you can choose to represent them in one of two ways.
Numeric variables with labeled values: If you choose Numeric variables with labeled values, Stat/Transfer will create a value label set and map it onto the numeric values. This is an appropriate choice for transferring the data into output formats that support value labels, such as SPSS, Stata, or SAS.
String variable: If you choose String Variables, Stat/Transfer will match the numeric variable to its string equivalent and write the string into your output dataset.
Write version one string missing
If you are using Version One of R, check this option and the appropriate value will be written for null or missing strings. If you are using a later version of R, leave this unchecked.