12.2 AUTORECODE

AUTORECODE VARIABLES=src_vars INTO dest_vars
        [ /DESCENDING ]
        [ /PRINT ]
        [ /GROUP ]
        [ /BLANK = {VALID, MISSING} ]

The AUTORECODE procedure considers the n values that a variable takes on and maps them onto values 1…n on a new numeric variable.

Subcommand VARIABLES is the only required subcommand and must come first. Specify VARIABLES, an equals sign (‘=’), a list of source variables, INTO, and a list of target variables. There must the same number of source and target variables. The target variables must not already exist.

AUTORECODE ordinarily assigns each increasing non-missing value of a source variable (for a string, this is based on character code comparisons) to consecutive values of its target variable. For example, the smallest non-missing value of the source variable is recoded to value 1, the next smallest to 2, and so on. If the source variable has user-missing values, they are recoded to consecutive values just above the non-missing values. For example, if a source variables has seven distinct non-missing values, then the smallest missing value would be recoded to 8, the next smallest to 9, and so on.

Use DESCENDING to reverse the sort order for non-missing values, so that the largest non-missing value is recoded to 1, the second-largest to 2, and so on. Even with DESCENDING, user-missing values are still recoded in ascending order just above the non-missing values.

The system-missing value is always recoded into the system-missing variable in target variables.

If a source value has a value label, then that value label is retained for the new value in the target variable. Otherwise, the source value itself becomes each new value’s label.

Variable labels are copied from the source to target variables.

PRINT is currently ignored.

The GROUP subcommand is relevant only if more than one variable is to be recoded. It causes a single mapping between source and target values to be used, instead of one map per variable. With GROUP, user-missing values are taken from the first source variable that has any user-missing values.

If /BLANK=MISSING is given, then string variables which contain only whitespace are recoded as SYSMIS. If /BLANK=VALID is specified then they are allocated a value like any other. /BLANK is not relevant to numeric values. /BLANK=VALID is the default.

AUTORECODE is a procedure. It causes the data to be read.

• Autorecode Example

12.2.1 Autorecode Example

In the file personnel.sav, the variable occupation is a string variable. Except for data of a purely commentary nature, string variables are generally a bad idea. One reason is that data entry errors are easily overlooked. This has happened in personnel.sav; one entry which should read “Scientist” has been mistyped as “Scrientist”. In Example 12.2 first, this error is corrected by the DO IF clause, ³ then we use AUTORECODE to create a new numeric variable which takes recoded values of occupation. Finally, we remove the old variable and rename the new variable to the name of the old variable.

get file='personnel.sav'. * Correct a typing error in the original file. do if occupation = "Scrientist". compute occupation = "Scientist". end if. autorecode variables = occupation into occ /blank = missing. * Delete the old variable. delete variables occupation. * Rename the new variable to the old variable's name. rename variables (occ = occupation). * Inspect the new variable. display dictionary /variables=occupation.

Example 12.2: Changing a string variable to a numeric variable using AUTORECODE after correcting a data entry error

Screenshot 12.1: Autorecode dialog box set to recode occupation to occ

Notice in Result 12.1, how the new variable has been automatically allocated value labels which correspond to the strings of the old variable. This means that in future analyses the descriptive strings are reported instead of the numeric values.

Variables Name Position Measurement Level Role Width Alignment Print Format Write Format occupation 6 Unknown Input 8 Right F2.0 F2.0 Value Labels Variable Value Label occupation 1 Artist 2 Baker 3 Barrister 4 Carpenter 5 Cleaner 6 Cook 7 Manager 8 Mathematician 9 Painter 10 Payload Specialist 11 Plumber 12 Scientist 13 Tailor

Result 12.1: The properties of the occupation variable following AUTORECODE