SPSS FREQUENCIES command can be used for much more than frequency tables: it's also the easiest way to obtain basic charts such as histograms and bar charts. On top of that, it provides us with percentiles and some other statistics. Plenty of reasons for taking a closer look at this ubiquitous SPSS command. We'll use employees.sav throughout this tutorial.
SPSS FREQUENCIES - Basic Table
The most basic way to use FREQUENCIES is simply generating a frequency table. For example, the frequency table for job_type is obtained by running the following line of SPSS syntax: frequencies job_type.
By default, the rows of this table are sorted ascendingly by value. Note that this may not be obvious when only value labels are displayed. We'll next take a look at different options for sorting the table rows.
SPSS FREQUENCIES - Sort Order
SPSS default sort order of ascendingly be value can be changed by adding a FORMAT subcommand. Possible values are AVALUE and DVALUE (ascending and descending values) or AFREQ and DFREQ (ascending and descending frequencies). For example, the syntax below sorts the rows from the value with highest frequency (yes, that's the mode) through the value with the lowest frequency.
SPSS FREQUENCIES - Bar Chart
SPSS FREQUENCIES command is the easiest way to create one or more bar charts for categorical variables. Just add the BARCHART subcommand. Note that you can combine it with a sort order, resulting in the barchart bars being ordered from highest through lowest frequency as shown below.
SPSS FREQUENCIES - Pie Chart
An alternative visualization for categorical variables is a pie chart. In order to generate it, simply add a PIECHART subcommand to FREQUENCIES. The syntax below creates a pie chart for education_type.
SPSS FREQUENCIES - Histogram
Frequency tables, bar charts and pie charts can all be used for both metric as well as categorical variables, including string variables. However, they are not useful for metric variables with many distinct values; in this case, tables get too many rows and graphs too many elements.
The ideal way to visualize such variables is a histogram, obtained by the HISTOGRAM subcommand. Apart from that, we can suppress frequency tables by specifying NOTABLE on the FORMAT subcommand. Like so, the syntax below generates a histogram for monthly_income.
SPSS FREQUENCIES - Percentiles
SPSS FREQUENCIES provides a nice way to obtain percentiles: just add a PERCENTILES subcommand followed by the desired percentiles in parentheses. The syntax below gives an example. Keep in mind that percentiles are not meaningful for nominal variables.
/percentiles (25 50,75).
SPSS FREQUENCIES - Ntiles
Ntiles are easily obtained with SPSS FREQUENCIES: simply add the NTILES subcommand with the number of ntiles behind it in parentheses. If you want to assign cases to ntile groups, use RANK; it creates a new variable holding the ntile for each case on a given variable. Both options are shown in the syntax below.
*2. Create monthly_income ntile group variable in data.
SPSS FREQUENCIES - Statistics
SPSS FREQUENCIES can compute all statistics obtained from DESCRIPTIVES plus the median and mode. Note that the statistics table from FREQUENCIES has a different layout with variables in columns and statistics in rows. For obtaining them, add a STATISTICS subcommand. Just as with DESCRIPTIVES, specifying the ALL keyword returns all available statistics.
SPSS FREQUENCIES - Multiple Variables
Obviously, FREQUENCIES can be run for multiple variables, possibly using TO or ALL. If multiple types of output (frequency table, chart and so on) are generated, you can have them sorted by variable or output type by specifying VARIABLE or ANALYSIS on an ORDER subcommand.
frequencies education_type to job_type
*2. Sort output by output type (first tables for all variables, then charts for all variables).
frequencies education_type to job_type