Expression evaluation

Facform provides a flexible method of obtaining the values of numbers and names by means of expressions. Expression evaluation is done as follows:


"..."  (text)

Quoted text. A value in quotes is a constant character value, e.g., "Mary"


number  (numeric value)

A value comprising digits, with or without a decimal point, is a constant numeric value, e.g., 23.4


+-*/^  (plus, minus, times, divide, exponent)

+ (plus), - (minus), * (multiply), / (divide), ^ (to the power of) are numeric operators. These are used in the evaluation of numeric quantities, e.g., 23+45  evaluates to 68.


+  (concatenate)

+ (plus) is used to put together, concatenate, character text.

E.g., "George"+" D. "+"Washington" evaluates to "George D. Washington".


><=  (greater, less, equal)

> (greater than), < (less than), = (equal to), >= (greater than or equal to), <= (less than or equal to), <> (not equal to) are used to compare values.


For numeric values, 23>12 yields the result of "true", or 1 as a numeric value. 23<12 yields the result of "false", or 0 as a numeric value.


For character values, "B">"A" yields the result of 1, meaning "true". "B"<"A" yields the result of 0 = "false", or 0 as a numeric value. Before character comparison, leading and trailing blanks are removed, e.g., "A   "="    A" is true, but "AB"="A   B" is false, because of the blanks between A and B.


&|  (and, or)

& (logical and), | (logical or) are used to combine numeric values, or the numeric outcome of <,>,=. A & B is 0 if either A or B or both are 0. A | B is 1 if either A or B or both are 1.

E.g., (A>1) & (B=0) evaluates to 0 if A is less than 1, or B is not zero.

(A=B) | (A=C) evaluates to 1 if A is equal to B or C, otherwise it is 0.


( )  (arrange order of expression evaluation)

Parentheses are used to set the order in which sub-expressions are evaluated. Evaluation proceeds from the inner-most sub-expression within parentheses outward. Otherwise, evaluation proceeds from left to right.

E.g., ((2+3)*(3+4)) evaluates to (5*(3+4)), then (5*7), then 35.

1+2*3 is evaluated left to right as (1+2)*3, then 3*3, then 9.

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Rasch Publications
Rasch Measurement Transactions (free, online) Rasch Measurement research papers (free, online) Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch Applying the Rasch Model 3rd. Ed., Bond & Fox Best Test Design, Wright & Stone
Rating Scale Analysis, Wright & Masters Introduction to Rasch Measurement, E. Smith & R. Smith Introduction to Many-Facet Rasch Measurement, Thomas Eckes Invariant Measurement with Raters and Rating Scales: Rasch Models for Rater-Mediated Assessments, George Engelhard, Jr. & Stefanie Wind Statistical Analyses for Language Testers, Rita Green
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar Journal of Applied Measurement Rasch models for measurement, David Andrich Constructing Measures, Mark Wilson Rasch Analysis in the Human Sciences, Boone, Stave, Yale
in Spanish: Análisis de Rasch para todos, Agustín Tristán Mediciones, Posicionamientos y Diagnósticos Competitivos, Juan Ramón Oreja Rodríguez
Winsteps Tutorials Facets Tutorials Rasch Discussion Groups


Coming Rasch-related Events
April 10-12, 2018, Tues.-Thurs. Rasch Conference: IOMW, New York, NY,
April 13-17, 2018, Fri.-Tues. AERA, New York, NY,
May 22 - 24, 2018, Tues.-Thur. EALTA 2018 pre-conference workshop (Introduction to Rasch measurement using WINSTEPS and FACETS, Thomas Eckes & Frank Weiss-Motz),
May 25 - June 22, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps),
June 27 - 29, 2018, Wed.-Fri. Measurement at the Crossroads: History, philosophy and sociology of measurement, Paris, France.,
June 29 - July 27, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps),
July 25 - July 27, 2018, Wed.-Fri. Pacific-Rim Objective Measurement Symposium (PROMS), (Preconference workshops July 23-24, 2018) Fudan University, Shanghai, China "Applying Rasch Measurement in Language Assessment and across the Human Sciences"
Aug. 10 - Sept. 7, 2018, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets),
Sept. 3 - 6, 2018, Mon.-Thurs. IMEKO World Congress, Belfast, Northern Ireland
Oct. 12 - Nov. 9, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps),



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