A Description of ASSOC
Yu Xie, University of Michigan

What is ASSOC?

ASSOC is a program for the analysis of association tables.� The original code was first developed by Leo Goodman and his former students at the University of Chicago and then made user-friendly by Clifford C. Clogg in a computer program called ANOASC for a wider distribution.� It was later modified by James W. Shockey in January, 1983.� Several modifications were made by Ruud Luijkx in 1985 and 1986.� First PC Implementation was in October 1986 (by Michael Massagli).� The latest update (that I know of) was made by Ruud Luijkx in December, 1988.� The ASSOC program deals with K separate I-by-J cross-tables and estimates Models corresponding to those in Goodman's 1979 JASA-Paper - Generalizations of both Model I and Model II are available.

The following input cards are required (each card is one line)

1. (A60) Title for run
2. (10I2) Input/Output information -- Place a 1 in :
���� Column 2 to suppress observed, expected counts and std.
residuals
���� Column 4 to suppress observed odds-ratios
���� Column 6 to suppress expected odds-ratios
���� Column 8 to suppress parameter estimates
���� Column 10 for Model II calculations (otherwise Model I
used)
���� Column 12 to suppress iteration detail
���� Column 14 if start tables are to be input
���� Column 16
������ If no specific diagonal parameters are to be included
�������� type in Column 16 zero. Otherwise:
������ 1� for free diagonals, i.e. each diagonal cell in every
�������� group has one diagonal parameter (quasi- models);
������ 2� for Group Specific Diagonal Parameters, i.e. one
�������� diagonal parameter for each group (table)
������ 3� for Category Specific Diagonal Parameters, i.e. one
�������� diagonal parameter for each diagonal cell for all
�������� groups (same density in the same diagonal cell in each
�������� table).
������ 4� Combination of 2 and 3: Group and Category Specific
�������� Effects
������ 5� One diagonal parameter for all diagonal cells

���� Column 18 to suppress the printing of Row and Column
Parameters
��
���� Column 20 to suppress the printing of Alpha- and Beta-
Ratios, or Mus, Nus and Mu- and Nu-Differences.

3. (2I2,I3,F8.7,I4,F4.3) #Rows, #Cols, #Groups,
���� Tolerance(def=.01) Iterations (def=100), Constant to be
���� added to all frequencies (def=.0)

4. Input Format for data -- e.g. any valid Fortran format;
���� examples: (8F6.0),(8X,7F5.3), or FREE

5. Name of file on which the data are stored in the above
���� Format

6. Input start tables (necessary only If column 14 of card #2
���� is 1) -- In the same Format as was used for the data,
���� place a 1 in those cells to be included and a 0 (zero) in
���� those to be ignored or excluded, i.e. treated as
���� structural zeroes.

7. (15I2) Model selection : Place a 1 in :
���� Column� 2 If Null Conditional Association (Conditional
Independence)
���� Column� 4 If Homogeneous Conditional Uniform Association
���� Column� 6 If Heterogeneous Conditional Uniform Association
���� Column� 8 If Homogeneous Conditional Row-Effects
���� Column 10 If Homogeneous Conditional Column Effects
���� Column 12 If Simple Heterogeneous Row Effects
���� Column 14 If Simple Heterogeneous Column Effects
���� Column 16 If Heterogeneous Row Effects
���� Column 18 If Heterogeneous Column Effects
���� Column 20 If Homogeneous Row and Column Effects
���� Column 22 If Heterogeneous Row, Homogeneous Column
���� Column 24 If Heterogeneous Column, Homogeneous Row
���� Column 26 If Heterogeneous Row and Column
���� Column 28 If Homogeneous Equal Row and Column Scalings
���� Column 30 If Heterogeneous Equal Row and Column Scalings

Example

(1) We store the following data (from Clogg 1982, AJS, Table 5)
���� in file "abort2.dat":

44� 11� 38� 62
59� 41 147 293
23� 11� 13� 27
27�� 8� 16� 27
258 57 105 110

(2) We edit a control file "abort2.ctl" as:

Replicating Clogg (1982), Data from Table 5
�0 0 0 0 1 1 0 0 0 0
�5 4� 1
FREE
abort2.dat
�1 0 0 0 0 0 0 0 0 0 0 0 1 0 0


In UNIX, enter:

assoc abort2.ctl abort2.dat abort2.log

Note: three arguments follow program "assoc": (1) control file,
���� (2) data file, and (3) output file

The following files are provided to you free of charge.� You
may copy, distribute, and use these files for education and
research purposes.

assoc.f������ Fortran source code
abort2.ctl��� A test program
abort2.dat��� Data on abortion attitude
abort2.log��� Output file from abort2.ctl
abortion.ctl� GLIM control file for comparison
abortion.log� GLIM output file from abortion.ctl