General Overview
All files should be stored in the directory C:\PCI
If this directory does not exist, you will need to create it.
File names should not contain any spaces.
To Calculate PCI2 in SPSS:
Download and unzip the SPSS PCI2 macro: SPSS_macro
Compile the macro that generates the PCI2
Highlight all code between
“DEFINE” (line 30)
and “!ENDDEFINE” (line 284)
Click the “Run” button
The following code generates the PCI2
| SPSS command | Comment |
| PCI2 infile=|’C:\PCI\Example.sav’| | Original input filename Replace “Example” with the name of your file |
| outfile=|’C:\PCI\Example.CSV’| | Output filename Replace “Example” with the name of your file |
| PCIOUT=|’C:\PCI\Sim_Data.sav’| | Output filename Do not change the name of this file |
| WORKDIR=|C:\PCI\| | Working directory (must be C:\PCI) |
| SubSample1=Sex SubSample2=??? SubSample3=??? Subsample4=??? |
Subsample(s) calculate PCI for each group (e.g., males and females in this example) Up to 4 Subsample variables can be specified. If the analysis does not have any Subsamples these lines can be eliminated |
| Scale_width=7 | Scale width (e.g., 2, 3, 4, 5, 6, 7, 8, 9) This example is based on a 7-point scale Replace the 7 with the width of your scale |
| var={VARIABLE NAME} | Variable to be used in PCI calculation |
| Distance_function=D1 | Distance Function: D1 (or D2) for bipolar scales D1 currently recommended for bipolar D3 for unipolar scales |
| Power_of_distance=|1.5 | Power: P1 = 1 = Unsquared difference scores P2 = 2 = Squared difference scores Power can be any value > 0 and < 5 |
The following files are examples of SPSS data, macro syntax, and output
| File type | File name |
| Data | Galapagos.sav |
| Syntax | Galapagos_macro.sps |
| Output | Galapagos_Frequencies_Crosstabs_output.spv |
| Output | Galapagos_PCI_output.spv |
The Galapagos.zip file contains the above four files.
Down load the ZIP file and unzip the files to a directory/folder where you can run the SPSS application.
In the Galapagos example:
The SubSample1 variable is “Island” (the respondent’s island of residence).
The Island variable has 3 responses:
1 = San Cristobal
2 = Santa Cruz
3 = Isabela
The macro calculates the PCI for the “normfish” variable (Norms for illegal fishing).
Because a SubSample variable was specified, 3 actual and 3 simulated PCI values are generated;
one for each of the islands.
The scale for “normfish” is 4-point unipolar (i.e., scale_width = 4):
0 = Do nothing if the fisherman violates the rules for illegal fishing
1 = Fine the fisherman
2 = Take away the fisherman’s permit for 15 days
3 = Take away the fisherman’s permit for the rest of the year
Note: The minimum value for a unipolar scale should always be 0.
Because the scale is unipolar, the appropriate distance function is D3.
The power of distance function is currently set to 1 (i.e., Power_of_distance = 1).