﻿ Expression evaluation

# 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.

Help for Facform Rasch Measurement Software: www.winsteps.com. Author: John Michael Linacre

 Forum Rasch Measurement Forum to discuss any Rasch-related topic

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
Jan. 5 - Feb. 2, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
Jan. 10-16, 2018, Wed.-Tues. In-person workshop: Advanced Course in Rasch Measurement Theory and the application of RUMM2030, Perth, Australia (D. Andrich), Announcement
Jan. 17-19, 2018, Wed.-Fri. Rasch Conference: Seventh International Conference on Probabilistic Models for Measurement, Matilda Bay Club, Perth, Australia, Website
Jan. 22-24, 2018, Mon-Wed. In-person workshop: Rasch Measurement for Everybody en español (A. Tristan, Winsteps), San Luis Potosi, Mexico. www.ieia.com.mx
April 10-12, 2018, Tues.-Thurs. Rasch Conference: IOMW, New York, NY, www.iomw.org
April 13-17, 2018, Fri.-Tues. AERA, New York, NY, www.aera.net
May 22 - 24, 2018, Tues.-Thur. EALTA 2018 pre-conference workshop (Introduction to Rasch measurement using WINSTEPS and FACETS, Thomas Eckes & Frank Weiss-Motz), https://ealta2018.testdaf.de
May 25 - June 22, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
June 27 - 29, 2018, Wed.-Fri. Measurement at the Crossroads: History, philosophy and sociology of measurement, Paris, France., https://measurement2018.sciencesconf.org
June 29 - July 27, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com
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" www.promsociety.org
Aug. 10 - Sept. 7, 2018, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com
Sept. 3 - 6, 2018, Mon.-Thurs. IMEKO World Congress, Belfast, Northern Ireland www.imeko2018.org
Oct. 12 - Nov. 9, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com

Concerned about aches, pains, youthfulness? Mike and Jenny suggest Liquid Biocell