Point-Biserial Correlation

1. Test Procedure in
SPSSStatistics
POINT-BISERIAL CORRELATION MARLOU F. FLORO
EDD-FLT

2. SPSSStatistics versions
27 and 28
and the subscription
version ofSPSSStatistics

3. Click Analyze
> Correlate
> Bivariate...
on the top
menu, as
shown below:

4. You will be
presented
with
the Bivariate
Correlations
dialogue box,
as shown
below:

5. •Transfer the
variables gender an
d engagement into
the Variables: box
by dragging-and-
dropping or by
clicking on the
button.

6. 3. Make sure that
the Pearson
checkbox is
checked in the –
Correlation
Coefficients– area
(although it is
selected by default
in SPSS Statistics),
as shown:

7. 4. Select
the Show only the
lower
triangle checkbox
and then deselect
the Show
diagonal checkbox
, as shown:

8. Click on the
button

9. SPSSStatistics version 26
and earlier versions of
SPSSStatistics

10. Click Analyze
> Correlate
> Bivariate... on
the menu system
as shown below:

11. You will be
presented with
the following
Bivariate
Correlations
screen:

12. Transfer the
variables gender
and engagement int
o the Variables: box
by dragging-and-
dropping or by
clicking on the
button.

13. Make sure that
the Pearson chec
kbox is checked
in the –
Correlation
Coefficients– area
(although it is
selected by
default in SPSS
Statistics).

14. Click on the
button. If you wish
to generate some
descriptives, you
can do it here by
clicking on the
relevant checkbox
in the –Statistics–
area.

15. Click on the
Click on the
button.
button.

16. Interpreting
the Point-
Biserial
Correlation
 If your data passed assumptions #3 (no outliers), #4
(normality) and #5 (equal variances), which we
explained earlier in the Assumptions section, you will
only need to interpret the Correlations table.
Remember that if your data failed any of these
assumptions, the output that you get from the point-
biserial correlation procedure (i.e., the table we
discuss below), will no longer be correct.

17. Interpreting
the Point-
Biserial
Correlation
 However, in this "quick start" guide, we focus on the results
from the point-biserial correlation procedure only, assuming
that your data met all the relevant assumptions. Therefore, if
you ran the point-biserial correlation procedure in the
previous section using SPSS Statistics version 27 or
the subscription version of SPSS Statistics, you will be
presented with the Correlations table below:

18. Interpreting
the Point-
Biserial
Correlation
Note: If you ran the point-biserial correlation
procedure using SPSS Statistics version 26 or
an earlier version of SPSS Statistics,
the Correlations table will look like the one below:

19. Interpreting
the Point-
Biserial
Correlation
 The Correlations table actually states that the “Pearson
Correlation” has been run because the point-biserial
correlation is simply a special case of Pearson’s product-
moment correlation, which is applied when you have two
continuous variables, whereas in this case one of the
variables is measured on a dichotomous scale. Therefore,
don’t be concerned that you have run a Pearson’s correlation
instead of a point-biserial correlation. As long as you have set
up your data correctly in the Variable View of SPSS Statistics,
as discussed earlier, a point-biserial correlation will be run
automatically by SPSS Statistics.
 The Correlations table presents the point-biserial correlation
coefficient, the significance value and the sample size that
the calculation is based on. In this example, we can see that
the point-biserial correlation coefficient, rpb, is -.358, and that
this is statistically significant (p = .023).

20. Reporting the
Point-Biserial
Correlation
 In our example above, you might present
the results as follows:
 General
 A point-biserial correlation was run to
determine the relationship between
engagement in an Internet advert and
gender. There was a negative correlation
between engagement and gender, which
was statistically significant (rpb = -.358, n =
40, p = .023).