
	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 <CTRL>O AND PRESSING <RETURN>.  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.

