Summated scales: Example

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Syntax for example

* The following command causes the cases to be weighted by the design weight variable 'dweight'.

WEIGHT BY dweight.

* The following commands causes SPSS to select for analysis those cases that belong to the British sample (value GB on country variable) and have lower values than 1975 on the birth year variable (& stands for AND, < stands for 'less than'). * In this process, the commands create a filter variable (filter_$) with value 1 for the selected cases and value 0 for the non-selected cases. * Change the last part of line 2 (which starts after the first equals sign) if you wish to select other cases (if you do this, you should also change the variablelabel, which can be found within double quotation marks on line 3).

COMPUTE filter_$=cntry = 'GB' & yrbrn < 1975.
VARIABLE LABEL filter_$ "cntry = 'GB' & yrbrn < 1975 (FILTER)".
VALUE LABELS filter_$ 0 'Not Selected' 1 'Selected'.
FORMAT filter_$ (f1.0).
FILTER BY filter_$.

* These commands compute summated scales.

COMPUTE Timesqueeze = (trdawrk + jbprtfp + pfmfdjb + dfcnswk)/4.
VARIABLE LABELS Timesqueeze 'Job - family time squeeze scale'.
COMPUTE badmoodscale = (gdsprt + clmrlx + actvgrs + frshrst + lfintr) / 5.
VARIABLE LABELS badmoodscale 'General bad mood scale'.

* These commands run multiple regression with summated scales and other ordinal variables.

/DEPENDENT badmoodscale
/METHOD=ENTER birthyear gender health wkhtot hincfel tngdohm lkafohh Timesqueeze.


We have computed two scales. One is intended to find out whether people feel that they are being squeezed between family responsibilities and their jobs. We call it the ‘Job-family time squeeze scale’. The other scale is supposed to elicit people’s general sense of wellbeing. We use SPSS’s ‘Compute Variable’ feature to create them. Check that ‘don’t know’ answers are coded as ‘User-missing’ before you make any computations. (There are other options, but they will not be discussed here.) As shown in Figure 17, the time-squeeze scale is computed by adding up the values of four indicator variables and by dividing this sum by the number of indicators. Hence, the scale value is the mean of the indicator variables. The indicator variables are the respondents’ accounts of how often they encounter the following problems.

Their values range between 1 (never) and 5 (always). Hence, the scale values also range between 1 and 5.


Figure 17. Computing a summated scale


The second scale is the mean of the values of the respondents’ reports about how often they have experienced the following during the last two weeks.

Note that, in this case, the order of the values has been reversed. ‘All of the time’ has value 1, while ‘At no time’ has value 6. Thus, the scale values become higher the less cheerful etc. people feel. Therefore, we have named the scale the ‘General bad mood scale’. Observe that we have created the scales for instructional purposes only. We do not make any claims as to their general applicability.

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