I am currently working on adapting the syntax for IAT.sps script for my dissertation. Without going into too much details, I will be working with 4 as opposed to 2 comparison groups. Where I am hung up on is the following section:
IF(TEST=1) ERR1a = ERR1 .
IF(TEST=1) ERR2a = ERR2 .
IF(TEST=2) ERR1b = ERR1 .
IF(TEST=2) ERR2b = ERR2 .
* These are the numerator components in millisecond units.
IF(TEST=1) M1a = M1 .
IF(TEST=1) M2a = M2 .
IF(TEST=2) M1b = M1 .
IF(TEST=2) M2b = M2 .
IF(TEST=1) SD1a = SD1 .
IF(TEST=1) SD2a = SD2 .
IF(TEST=2) SD1b = SD1 .
IF(TEST=2) SD2b = SD2 .
IF(TEST=1) N1a = N1 .
IF(TEST=1) N2a = N2 .
IF(TEST=2) N1b = N1 .
IF(TEST=2) N2b = N2 .
COMPUTE D_asis_num = M2 - M1.
My adapted section looks like:
F(TEST=1) ERR1a = ERR1 .
IF(TEST=1) ERR3a = ERR3 .
IF(TEST=1) ERR4a = ERR4 .
IF(TEST=2) ERR3b = ERR3 .
IF(TEST=2) ERR4b = ERR4.
IF(TEST=1) M3a = M3 .
IF(TEST=1) M4a = M4 .
IF(TEST=2) M3b = M3 .
IF(TEST=2) M4b = M4 .
IF(TEST=1) SD3a = SD3 .
IF(TEST=1) SD4a = SD4 .
IF(TEST=2) SD3b = SD3 .
IF(TEST=2) SD4b = SD4 .
IF(TEST=1) N3a = N3 .
IF(TEST=1) N4a = N4 .
IF(TEST=2) N3b = N3 .
IF(TEST=2) N4b = N4 .
COMPUTE D_asis_num = M2 - M1. <--- this is there I am stuck. Would my D_asis_num simply be M4-M1, or M4-M3-M2-M1? I haven't quite figured out the spss syntax language, so I am basically going trial and error here. Thanks in advance!!
note: I realize the first IF statement of my adapted section is missing the "I". it's there in my script, but didn't get copied into the forum post. Thanks again.
This post contains a rather detailed explanation of what M1 and M2 are in the original SPSS syntax:
http://www.millisecond.com/community/forums/p/1370/4383.aspx#4383
Then just extend the logic to your modified procedure.
Regards,
~Dave
"To understand recursion, you must first understand recursion." - Unknown Zen Master
thanks Dave, that cleared it up for me. it looks like i'll need two separate computations (one for 1 and 2, a second for 3 and 4) b/c i want to obtain two separate mean latencies (based on two different sets of conditions). . do i need to differentiate the COMPUTE D_asis_num and _denom statements in any way (e.g., adding a 1 or A), or will that mess up the syntax? thanks for a quick responses.
Well, since I virtually know nothing about your modifications to the standard IAT procedure, I really can't tell. The best advice I can give you is to first get a good understanding of how the original SPSS syntax works / what each step does* and then decide for yourself.
Good luck,
* Recent SPSS versions feature stepwise syntax execution, which may be helpful in figuring this out; adding your own comments to the syntax is also a good idea.