CROSS  -----   THE FORTRAN PROGRAM CROSS INCORPORATES MANY OF THE FEATURES OF  THE DISCRETE BRANCH OF PROJECT IMPRESS DEVELOPED AT DARTMOUTH  COLLEGE. USERS FAMILIAR WITH IMPRESS WILL NOTE CERTAIN DIFFER-  ENCES, SUCH AS A SIMPLIFICATION OF THE COMMAND HIERARCHY AND THE  FACT THAT VARIABLES AND CATEGORIES ARE NUMBERED INSTEAD OF BEING  LABELED.   CROSS IS INTENDED FOR THE ANALYSIS OF DATA COLLECTED WHOLLY OR  PARTLY BY THE USER, AS, FOR EXAMPLE, A SURVEY CONDUCTED BY A  SOCIAL SCIENCE CLASS. OBSERVATIONS OR RESPONSES ARE TO BE CODED  ACCORDING TO CERTAIN RULES AND THE DATA, PRESUMABLY PUNCHED ON  CARDS, READ INTO A DATA FILE BY MEANS OF THE FORTRAN PROGRAM  SURVEY. PROSPECTIVE USERS OF CROSS SHOULD REFER TO THE INSTRUC-  TIONS FOR THE PROGRAM SURVEY.   BEFORE RUNNING THE PROGRAM CROSS TO ANALYZE THE DATA, THE USER  MAY FIND IT HELPFUL TO OBTAIN A PRELIMINARY TABULATION OF RE-  SPONSES WITH THE PROGRAM SORTER.    PROGRAM CROSS  (CORRELATION OF RESPONSES WITH OPTIONS FOR THE SOCIAL SCIENCES)   DESCRIPTION  THIS PROGRAM CORRELATES RESPONSES TO SELECTED QUESTIONS OF A  QUESTIONNAIRE TO PRODUCE A TABLE OF MARGINAL FREQUENCIES FOR  ANY VARIABLE OR CROSS-TABULATIONS OF PAIRS OF VARIABLES (WITH  OR WITHOUT A CONTROL VARIABLE) GIVING FREQUENCIES, PERCENTAGES,  OR OTHER STATISTICS DESIRED BY THE USER. AN EXCLUSION ANALYSIS  IS MADE IN EVERY CASE. AN ITEM ANALYSIS MAY BE CARRIED OUT ON A  SELECTED SET OF VARIABLES AND THE RESULTS TABULATED AS A MATRIX  OF ITEM INTERCORRELATIONS. IN ADDITION, A MAPPING OPTION ALLOWS  RESPONSES TO BE GROUPED INTO NEW CATEGORIES, WHILE JOINING AND  POOLING OPTIONS LET THE USER CONSTRUCT NEW VARIABLES. MODIFIED  VERSIONS OF THE DATA FILE MAY BE SAVED FOR USE IN SUBSEQUENT  RUNS OF THE PROGRAM. THE USER HAS ACCESS AT ALL TIMES TO EVERY  VARIABLE IN THE SURVEY (AS MANY AS 128).   THE DATA ANALYSIS PART OF THIS PROGRAM IS AVAILABLE SEPARATELY  AS CROSS1. THE DATA MANIPULATION PART CAN BE RUN SEPARATELY AS  CROSS2.   SOURCE  NORMAN W. JOHNSON, DEPARTMENT OF MATHEMATICS, WHEATON COLLEGE,  NORTON, MASS.   INSTRUCTIONS  THE CODED RESPONSES TO THE QUESTIONNAIRE SHOULD BE READ FROM  CARDS AND WRITTEN INTO AN ASCII DATA FILE BY THE PROGRAM SURVEY.  A PRELIMINARY TABULATION OF MARGINAL FREQUENCIES FOR ALL VARI-  ABLES THE USER INTENDS TO WORK WITH CAN BE OBTAINED BY RUNNING  THE PROGRAM SORTER.   THE PROGRAM WILL FIRST REQUEST THE USER TO ENTER THE NAME OF  THE DATA FILE. AFTER THIS IS DONE, A DESCRIPTION OF THE SURVEY  WILL BE TYPED. THE USER MAY THEN PROCEED TO ANALYZE THE DATA BY  GIVING ONE OF THE COMMANDS "XTAB" OR "ITEM", MAY REDEFINE OR RE-  STORE CATEGORIES WITH ONE OF THE COMMANDS "MAP" OR "UNMAP", MAY  CONSTRUCT OR DELETE VARIABLES WITH ONE OF THE COMMANDS "JOIN",  "POOL", OR "CUT", MAY TYPE "SAVE" TO PRESERVE THE CURRENT FORM  OF THE DATA AS A NEW FILE, MAY RESTORE THE ORIGINAL FORM OF THE  DATA WITH THE COMMAND "RESET", OR MAY TERMINATE THE EXECUTION OF  THE PROGRAM BY TYPING "STOP".   COMMANDS THAT TAKE VARIABLES AS ARGUMENTS MAY HAVE THE LIST OF  VARIABLES ENTERED ON THE SAME LINE AS THE COMMAND.   THE COMMAND "XTAB" ENABLES THE USER TO OBTAIN MARGINAL FREQUEN-  CIES FOR ANY ONE VARIABLE OR TO CROSS-TABULATE ANY PAIR OF VARI-  ABLES, USING A THIRD VARIABLE AS A CONTROL IF DESIRED. THE  CONTROL VARIABLE MAY BE RESTRICTED TO ONE CATEGORY BY FOLLOWING  THE THIRD VARIABLE NUMBER WITH AN EQUALS SIGN (=) AND A CATEGORY  NUMBER (0 TO 9). FOLLOWING THE THIRD VARIABLE NUMBER WITH AN  INEQUALITY SIGN (<>) AND A CATEGORY NUMBER HAS THE EFFECT OF  EXCLUDING RESPONDENTS IN THAT CATEGORY. IF TWO OR THREE VARI-  ABLES ARE SPECIFIED, ONE OR MORE OUTPUT OPTIONS MUST BE SELECTED  AND THE APPROPRIATE CODE NUMBERS ENTERED. THE FOLLOWING OPTIONS  ARE AVAILABLE:   0--EXCLUSION ANALYSIS ONLY  1--FREQUENCY OF RESPONSES  2--PERCENTAGES ACROSS  3--PERCENTAGES DOWN  4--PERCENTAGES OF TOTAL  5--CHI-SQUARE, DEGREES OF FREEDOM, AND PROBABILITY  6--GOODMAN AND KRUSKAL'S TAU  7--YULE'S Q OR GOODMAN AND KRUSKAL'S GAMMA  8--PHI COEFFICIENT OR KENDALL'S TAU  9--SOMER'S D   THE COMMAND "ITEM" PRODUCES A MATRIX OF ITEM INTERCORRELATIONS  (GOODMAN AND KRUSKAL'S GAMMA) FOR AS MANY AS NINE VARIABLES. A  VARIABLE PRECEDED BY A MINUS SIGN HAS ITS CATEGORIES REVERSED.  WHEN THE COMMAND IS GIVEN AS "ITEM PART", A CONTROL VARIABLE MAY  BE SPECIFIED. CORRELATIONS MAY BE LIMITED TO A CERTAIN SET OF  RESPONDENTS BY FOLLOWING THE CONTROL VARIABLE WITH AN EQUALITY  OR INEQUALITY SIGN AND A CATEGORY NUMBER.   THE COMMAND "MAP" ENABLES THE USER TO REGROUP THE RESPONSES TO  ANY QUESTION. FOR EACH VARIABLE OR BLOCK OF VARIABLES, THE USER  SPECIFIES HOW MANY NEW CATEGORIES ARE TO BE CREATED, THEN LISTS  THE CODE NUMBERS (0 TO 13) OF THE RESPONSES TO BE INCLUDED IN  EACH GROUP. NUMBERS MAY BE LISTED INDIVIDUALLY, SEPARATED BY  COMMAS, OR TWO NUMBERS MAY BE JOINED BY A HYPHEN TO FORM A BLOCK  OF CONSECUTIVE RESPONSES. BY TYPING "1" OR "KEEP" WHEN THE NUM-  BER OF NEW CATEGORIES IS REQUESTED, THE USER MAY PRESERVE THE  CURRENT GROUPING. TYPING "0" OR "UNMAP" RESTORES THE ORIGINAL  CODING. TYPING "-1" OR "REFLECT" REVERSES THE EXISTING CATE-  GORIES. TYPING "X" OR "EXCLUDE" ELIMINATES ALL CATEGORIES. A  LIST OF THE CURRENT CATEGORIES MAY BE OBTAINED BY TYPING "LIST".   AFTER EACH MAPPING THE USER MUST INDICATE WHETHER ANY CATEGORIES  ARE TO BE EXCLUDED. IF NOT, AN EXCLUSION CODE OF 0 IS ENTERED.  OTHERWISE, THE EXCLUSION CODE IS 1 IF THE USER DESIRES TO OMIT  THE HIGHEST NUMBERED CATEGORY, 2 IF THE TWO HIGHEST CATEGORIES  ARE TO BE OMITTED, ETC. LIKEWISE, AN EXCLUSION CODE OF -1 MAY  BE USED TO OMIT THE LOWEST NUMBERED CATEGORY, AND SO ON. AN EX-  CLUSION CODE CANNOT LEAVE FEWER THAN TWO CATEGORIES. HOWEVER,  THE USER MAY TYPE "X" TO ELIMINATE ALL CATEGORIES.   THE COMMAND "UNMAP" CANCELS THE EFFECT OF THE CURRENT MAPPING OF  THE VARIABLE OR VARIABLES SPECIFIED, THUS RESTORING THE ORIGINAL  CODING OF THE RESPONSES TO EACH QUESTION. THE ORIGINAL CODING  IS ALSO RESTORED WHEN THE PROGRAM IS RUN FROM THE BEGINNING,  UNLESS A MODIFIED VERSION OF THE DATA FILE HAS BEEN SAVED.   THE COMMAND "JOIN" ALLOWS THE USER TO COMBINE TWO OR THREE VARI-  ABLES INTO ONE NEW VARIABLE. ALL COMBINATIONS OF CATEGORIES  FOR THE GIVEN VARIABLES ARE ARRANGED IN A TABLE, WHICH THE USER  FILLS IN WITH THE NUMBERS (0 TO 9 WITH 11, 12, AND 13 FOR EX-  CLUSIONS) TO BE ASSIGNED TO THE CORRESPONDING CATEGORIES OF THE  NEW VARIABLE. AS IN THE CASE OF THE "XTAB" COMMAND, WHEN THREE  VARIABLES ARE LISTED, THE USER MAY SELECT OR REJECT A PARTICULAR  CATEGORY OF THE THIRD VARIABLE. THE "JOIN" COMMAND ALSO ALLOWS  SINGLE VARIABLES TO BE DUPLICATED AND PROVIDES A WAY OF HANDLING  VARIABLES WITH TWO- OR THREE-DIGIT CATEGORY NUMBERS.   THE COMMAND "POOL" MAY BE USED TO CONSTRUCT AN INDEX VARIABLE  FROM A BLOCK OF VARIABLES WITH SCALED RESPONSES, E.G., QUESTIONS  DESIGNED TO MEASURE RESPONDENTS' ATTITUDES. THE TOTAL SCORE OF  EACH RESPONDENT FOR THE BLOCK OF QUESTIONS IS COMPUTED, DIVIDED  BY THE NUMBER OF QUESTIONS, AND ROUNDED TO THE NEAREST INTEGER.  THE RESULTING CATEGORY NUMBER PLACES THE RESPONDENT ON A SCALE  FOR THE INDEX VARIABLE COMPARABLE TO THE ONE EMPLOYED FOR THE  VARIABLES USED TO CONSTRUCT IT.   THE COMMAND "CUT" PERMITS THE DELETION OF THE HIGHEST NUMBERED  VARIABLE OR VARIABLES, EITHER TO MAKE ROOM FOR NEW VARIABLES TO  BE CREATED BY JOINING OR POOLING OR TO ELIMINATE ONE OR MORE OF  THOSE MOST RECENTLY CREATED. THE USER SPECIFIES THE NUMBER OF  VARIABLES TO BE REMOVED BY ENTERING A DELETION CODE.   THE COMMAND "SAVE" ENABLES THE USER TO PRESERVE THE CURRENT FORM  OF THE DATA, INCORPORATING ALL MAPS, JOINS, POOLS, AND CUTS, AS  A NEW DATA FILE. THIS FILE MUST BE GIVEN A NAME, DIFFERENT FROM  THAT OF ANY EXISTING DATA FILE, CONSISTING OF FROM ONE TO FIVE  CHARACTERS. THE NAME MAY BE SPECIFIED IN THE "SAVE" COMMAND  (E.G., "SAVE FILNM") OR SEPARATELY.   THE COMMAND "RESET" RESTORES THE INITIAL STATE OF THE DATA, THUS  UNDOING THE EFFECTS OF ALL MAPS, UNMAPS, JOINS, POOLS, AND CUTS.   AFTER ANY OF THE ABOVE COMMANDS IS CARRIED OUT, A NEW COMMAND  MAY BE GIVEN. THE USER MAY SUPPRESS THE PRINTING OF TABLES OR  ANY OTHER OUTPUT IN ORDER TO GIVE A NEW COMMAND IMMEDIATELY BY  TYPING O AND PRESSING . FURTHER EXECUTION OF A  COMMAND MAY BE HALTED AT ANY BREAK POINT BY TYPING "ABORT".   WHENEVER THE USER IS EXPECTED TO GIVE A COMMAND OR TO PROVIDE  CERTAIN INFORMATION NEEDED FOR THE EXECUTION OF A COMMAND, AN  EXPLANATION OF WHAT IS REQUIRED MAY BE OBTAINED BY TYPING THE  WORD "EXPLAIN" OR SIMPLY A QUESTION MARK.   THIS PROGRAM ASSUMES THAT OUTPUT IS TO THE USER TERMINAL. IF  OUTPUT TO A FILE ON THE DISK IS DESIRED INSTEAD, THE DISK SHOULD  BE ASSIGNED LOGICAL UNIT 5 PRIOR TO RUNTIME.   REMARKS  THE COMPUTED VALUE OF CHI-SQUARE WITH ONE DEGREE OF FREEDOM  INCORPORATES A CORRECTION FOR CONTINUITY. THE CALCULATION OF  CHI-SQUARE IS ACCOMPANIED BY A WARNING IF THE EXPECTED FREQUENCY  IS LESS THAN 1 IN ANY CELL OR LESS THAN 5 IN MORE THAN 20 PER  CENT OF THE CELLS. KENDALL'S TAU HAS A CORRECTION FOR TIES.   REFERENCES  JAMES A. DAVIS, 'ELEMENTARY SURVEY ANALYSIS', PRENTICE-HALL,  ENGLEWOOD CLIFFS, N.J., 1971.  JOHAN GALTUNG, 'THEORY AND METHODS OF SOCIAL RESEARCH', COLUMBIA  UNIVERSITY PRESS, NEW YORK, 1967.  E. TERRENCE JONES, 'CONDUCTING POLITICAL RESEARCH', HARPER &  ROW, NEW YORK, 1971.