David A. Kenny
May 15, 2011
APIM (Indistinguishable Dyads) Macro
macro, called APIMText, was written by David A. Kenny, Department of
I thank Linda Acitelli for the sample data.
The dataset needs to be in pairwise format. To convert an individual file to a pairwise data click here.
I have created a Frequently Asked Questions page. If you have questions click here.
APIMText (You need SPSS to open this and the next 3 files.)
Macro Output (You do not need SPSS to open this file.)
To understand how to run a macro return to the DataToText page. The macro may take a minute or two to run and so be patient. Also make sure to backup the raw data file, as sometimes an error in the macro can alter the data file. If using a MAC, search for "c:\apimtext.dat" in the macro and change "c" to "Macintosh HD". Note variables will be added to data file. YOU SHOULD BACKUP YOUR DATA FILE! The text file is NOT contained in the SPSS output file. It is contained in a file called “c:\apimtext”. Look for it there!
The Macro Call
This is the statement for the sample data:
APIMText a = RSpouse/p = PSpouse /y = RSatisfied/dyadid = coupleid
xn = 'Other Positivity' yn = 'Satisfied' alpha=.05.
The defaults are as follows:
a = Actor
p = Partner
y = Outcome
dyadid = dyadid
xn = X
yn = Y
oflile = c:\apimtext.txt
directory = c:\
That is, if you just say “APIMText.”, the program will assume that are variables in the SPSS data file with variables named Actor, Partner, and M.
APIMText was written on SPSS 16 and 18 there is no guarantee that it work on earlier or later versions of SPSS.
Variables in the macro:
a = the name of actor variable in the SPSS data set
p = the name of actor variable in the SPSS data set
y = the name of outcome variable in the SPSS data set
dyadid = the name of outcome variable in the SPSS data set
xn = the name for X variable (actor and partner) to be used in the text file
yn = the name for the outcome variable to be used in the text file
alpha = significance level (defaults to .05)
ofile = the name of the output file (use quotes); this is where you go to find the text; defaults to c:\apimtext.txt; if your computer does not allow you write on the c drive or does not have a c drive, you must change this
directory = the name of the directory where temporary files are written (use quotes); this must be a directory you are allowed to write on; defaults to c:\; if your computer does not have a c drive or does not allow you to write on it, you must change this
clist = the SPSS names of the covariates separated by spaces; defaults to blank.
Note carefully what terms have quotes and what do not and where the slashes are where they are not and the defaults. The output file is currently written to a file named "c:\APIMtext.dat".
Look for updates, as there are likely to be errors. No guarantee for accuracy. Almost certainly you will need to edit the DataToText output in research reports. There will be updates. There is no guarantee for accuracy. Examine not only DataToText output file, but also the SPSS output file. The user needs to carefully edit the ApimText output in research reports. Please cite this ApimText webpage if you do use it. Moreover, you need a footnote that says: “Some of the material here was produced by the SPSS macro ApimText (Kenny, 2011).”
ApimTextprovides five possible warnings. The user needs to pay careful attention to them. Note that the example below produces two warnings.
3. The actor and partner variables are highly correlated and this colinearity compromises the analysis.
4. Because zero is not a possible value for actor variable ,grand-mean centering that variable should be considered.
5. Because the actor variable is a dichotomy, the product term and discrepancy score are perfectly correlated and only one of the two should be reported.
WARNINGS: 1. Because zero is not a possible value for Other Positivity, grand-mean centering that variable should be considered.
ACTOR-PARTNER INTERDEPENDENCE MODEL
The focus of this study is the investigation of the effect of Other Positivity on Satisfaction. Both the effect of own Other Positivity (actor) and the effect of partner's Other Positivity (partner) on Satisfaction are studied. There are a total of 148 dyads and no missing data. The total number of individuals is 296. The means and standard deviations are presented in Table 1.
The actor effect is equal to .400 and is statistically significant (p < .001), with a medium effect size (Beta = .402). The partner effect is equal to .288 and is statistically significant (p < .001), with a small effect size (Beta = .289). A summary of actor and partner effects is contained in Table 2. The intraclass correlation is equal to .469. Thus, the two members of the dyad are similar to one another. The pseudo R squared (Kenny, Kashy, & Cook, 2006) is equal to .295. There is evidence for "couple model" (Kenny & Cook, 1999) in that the actor and partner effects are not significantly different. It may make sense to sum or average the two Other Positivity scores.
The actor-partner interaction is equal to -.295 and is statistically significant (p = .019). The partner effect for persons who are one standard deviation above the mean on Other Positivity is .146 and for persons who are one standard deviation below the mean on Other Positivity is .441. Alternatively, the effect of the absolute difference of the two members on Other Positivity is equal to .019 and is not statistically significant (p = .819). Thus, if two members have the same score on Other Positivity, their score on Satisfaction is .019 units lower than it is for a dyad whose scores on Satisfaction differ by one unit. There is evidence for an actor-partner interaction.
Table 1: Descriptive Statistics
Variable Mean Standard Deviation
Other Positivity 4.264 .498
Satisfaction 3.605 .496
Table 2: Effect Estimates
Effect Coefficient Beta df p value
Actor .400 .402 273.1 <.001
Partner .288 .289 273.1 <.001
Other Positivity 1 _________________________> Satisfaction 1
/\ \ /\ /\
/ \ / \
( \ / \
( \ / \
( \ / E1
( \ / )
.058* [ X ] .082*
( / \ )
( .288* / \ .288* E2
( / \ /
( / \ /
\ / \ /
\/ / .400* \/ \/
Other Positivity 2 _________________________> Satisfaction 2
* p < .05
Kenny, D. A., & Cook, W. (1999). Partner effects in relationship research: Conceptual issues, analytic difficulties, and illustrations. Personal Relationships, 6, 433-448.
Kenny, D. A., Kashy, D. A., & Cook,
W. (2006). Dyadic data