Educator Presenters


Dewey Sadka

For more than 25 years, Dewey Sadka owned and ran Temp Force, one of the nation’s largest and most successful staffing companies. Frustrated with the inability of other evaluations to predict “who would most ENJOY day-to-day job tasks,” he created a multi-patented system that is now the world’s most accurate career evaluation—higher than Myers Briggs® with a .80+ correlation. His system predicts best occupations and all five global personality factors without language. Over 60 million visitors visited his website last year, with 10 and features. He is also the author of a series of books through Random House and a well-known national speaker.


Rense Lange, Ph.D.

1997 – Current   Psychometrician. Illinois State Board of Education (ISBE), Springfield, IL.

* Technical design, pilot testing, IRT scaling, quality control, (vertical) scaling/ equating, design of technical manuals, and DIF analyses in annual testing of 1.5 million Illinois students, including analyses of “No Child Left Behind” issues.
* Quality control of scoring of open-ended (short-) answer questions on reading and mathematics tests.
* Psychometric review of the equating of the legally required Illinois Teacher Certification Test (ICTS) taken by all Illinois teacher candidates. This test covers reading, language arts, mathematics, and writing.
* Conduct statewide workshops for teachers and administrators to explain state testing results, including presentations of basic statistical concepts, test construction, IRT, and introduction to analyzing school and student data with Excel.
* Psychometric liaison with large-scale testing contractors (ACT, Harcourt, Metritech, NCS-Pearson), organize and contribute to advisory and technical committees, bias review and standard setting groups. Analysis of Illinois’ and international TIMSS data sets. Respond to FOIA requests and press interviews.
* Software: Bilog, Bigsteps, ConQuest, Winsteps, Facets, SPSS, Mathcad, S-Plus, R, Axum, SIBTEST, Poly-SIBTEST, DIMTEST, WinMira, Multilog, Parscale, Pascal, C, C#, Delphi, Fortan, iText and Prawn pdf-writers, Gensim, JAVA, Lisp, Python, NTLK Language Toolkit, Ruby, and Prolog. Windows, UNIX, Linux, Mac OS.


2003 – Current CEO and Founder of Integrated Knowledge Systems (see: IKS specializes in the design, implementation, and marketing of computer adaptive testing (CAT) technology based on Item-Response Theory and applications of Latent Semantic Indexing (LSA / LSI) and related methods (e.g., LDA). Customers include companies in online assessment (academic and personnel oriented), social networking and dating sites, government (e.g., the US Army Research Institute), pharmaceutical supplies companies, and hospitality valuation. Applications include:

* Online personnel testing, and testing related to social networking and work-group formation. In addition, we focus on research and applications in crowdsourcing.
* IKS applied LSA and related methods to score large quantities of free-style written prose. This works extends basic research conducted under contract with the US Army Research Institute (ARI), where RL functioned as Senior Research Scientist.
* IKS applied natural language processing of human written statements in a wide range of contexts: interpreting of written customer feedback statements, the evaluation of students’ typed answers to open-ended questions during CAT, identifying personality traits via computer based linguistic analysis of written artifacts, and brand-protection.
* IKS designed and implemented LSA systems to capture buyers’ and commentators’ sentiments surrounding a particular brand or product (

2007 – Current : Scientific Advisor to the Portugal-Israel Chamber of Commerce (Porto,


1999 – 2003     Adjunct Associate Professor of Psychiatry. Southern Illinois School of Medicine (SIU), Springfield, IL. Research on the early detection of Alzheimer’s disease using the University of Pennsylvania Smell Identification Tests (UPSIT) via standard and CAT based Rasch scaling models. Redesign to increase sensitivity to younger (i.e., healthier) respondents in order to detect early onset of Alzheimer’s related diseases.

1988 – 1996 Assistant Professor of Computer Science and Psychology. University of Illinois at Springfield, IL (UIS).

* Computer Science: Taught computer organization, operating systems, computer languages (undergraduate), compilers, artificial intelligence (graduate).
* Psychology: Taught general psychology, experimental psychology and research methods, elementary to intermediate social statistics, cognitive psychology, social psychology of attitudes and impression formation (graduate).
* Advisor on students’ Master’s level theses in computer science, education, and psychology. Headed undergraduate psychology research teaching laboratory.

1981 – 1983     Visiting Assistant Professor of Psychology, University of Illinois at Urbana-Champaign. Taught statistics, social, experimental, and organizational psychology, and using computer systems for research purposes.

Member    American Psychological Association, American Educational Research Association, Institute for Objective Measurement, American Marketing Association.

Languages    Dutch: native. English: near native. French: fluent in speaking, reading, listening, less fluent in writing. German: fluent in reading and understanding, less fluent in speaking and writing.


1989                  ABD in Computer Science (AI), University of Illinois at Urbana-Champaign.
1986                  MA in Computer Science (software / AI), University of Illinois at Urbana-Champaign.
1981                  PhD in Psychology (social/experimental), University of Illinois at Urbana-            Champaign.
1977                  Masters in Psychology (social / experimental / quantitative), Rijks Universiteit Groningen, the Netherlands.


Lange, R., and Lange, X. (2012). Quality control in crowdsourcing: An Objective Measurement approach to identifying and correcting rater effects in the social evaluation of products and services. Paper to be presented at the AAAI Spring Symposium, Stanford University. March 26, 2012.

Arce-Ferrer, A., and Lange, R. (2012). Monitoring the quality of performance assessment raters. Paper to be presented at the 8-th Conference of the International Test Commission (ITC). Amsterdam, The Netherlands, July 3-5, 2012.

Arce-Ferrer, A., and Lange, R. (2012). Effects of linguistic accommodations on mathematics test scores and reported skills diagnostics. Paper to be presented at the 2012 NCME Annual Meeting. Vancouver, BC. April 12-16.

Lange, R., Houran, J., and McCutcheon, L.E. (2011). Celebrity and Parasocial Interaction. In: Brewer, G., Media Psychology. Basinstoke, UK: Palgrave MacMillan, p. 115-132.

Lange, R. (2012, under review). Combining LSI and statistical classification rules in augmenting quality control indices in crowdsourcing and customer evaluations.

Lange, X., and Lange, R. (2011). Haskell Possibilities for CAT. Paper presented at the 2011 International Association for Computerized Adaptive Testing Conference. Pacific Grove, California, October 3-5.

Lange, R., Stevens, D., and Schwarz, P. (2011). Some Surprising Dynamics of “Technology Enhanced” Item Types: Taking Additional Time is Associated with Increased Student Performance on Some Types of Items, while Decreasing Performance on Others. 2011 International Association for Computerized Adaptive Testing Conference. Pacific Grove, California, October 3-5, 2011.

Birjandi, P., Daftarifard, P., and Lange, R. (2011). The effects of dynamic assessment on Rasch item and person hierarchies in second language testing. International Journal of Language Studies (IJLS), Vol. 5, Issue 1, 125-140.

Lange, R. (2010, June 6 – 9). An adaptive scheme for the dynamic Rasch calibration of pilot items. Poster presented at the first IACAT, Arnhem, the Netherlands.

Lange, R., and Houran, J. (2010). A transliminal view of intuitions in the workplace. North American Journal of Psychology, 2010, Vol. 12, No. 3, 501-516.

Daftari Fard, P., and Lange, R. (2008). Theoretical complexity vs. Rasch item difficulty in reading tests. Rasch Measurement Transactions, 2009, 23:2, p. 1212-1213.

Fishbein, M., & Lange, R. (1990). The effects of crossing the midpoint on belief change: A replication and extension. Personality and Social Psychology Bulletin, 16, 189-199.
Harandi, M.T. & Lange, R. (1990). Model Based Knowledge Acquisition. In: Adeli (Ed.). Knowledge Engineering. New York, NY: Addison-Wesley.
Houran, J., Lange, R., Rentfrow, P. J., & Bruckner, K. H. (2004). Do online matchmaking tests work? An assessment of preliminary evidence for a publicized ‘predictive model of marital success.’ North American Journal of Psychology, 6, 507-526.
Illinois TIMSS Task Force (1997). An initial analysis of the Illinois results from the Third International Mathematics and Science Study (TIMMS). Illinois State Board of Education, Springfield, Illinois, September 17, 1997. (Co-author).
Kazuaki, U. and Lange, R. (2000, April 24-28). An International Perspective on Eight Grade Mathematics in Rural, Urban, and Suburban Schools: The United States vs. Korea. Paper presented at the 81st Annual Meeting of the American Educational Research Association, New Orleans.
Lange, R. (2008). Binary Items and Beyond: Simulation of Computer Adaptive Testing Using the Rasch Partial Credit Model. Journal of Applied Measurement, Vol. 9.
Lange, R. (2007, Feb 15-20). Technical Demands on the Large Scale Implementation of Student Assessments. I Bienal da Aprendizagem da Matemática e do Português (ISCTEM). Maputo, Mozambique.
Lange, R. (2007). Binary Items and Beyond: A Simulation of Computer Adaptive Testing Using the Rasch Partial Credit Model. In: Smith, E. and Smith, R. (Eds.) Rasch Measurement: Advanced and Specialized Applications. Pp. 148-180, Maple Grove, MN: JAM Press.
Lange, R. (2003, April 25-27). RASCHLAB: Using Computer Simulation to Teach Objective Measurement. Presentation at the FESTSCHRIFT in honor of Ben Wright: Access, Provocation, and the Development of Professional Identity: Celebrating the Careers of Benjamin D. Wright. Chicago, IL.
Lange, R. (1999). A cusp catastrophe approach to the prediction of temporal patterns in the kill dates of individual serial murderers. Nonlinear Dynamics, Psychology, and Life Sciences, 3, 143-159.
Lange, R. (1996). An empirical test of the weighted effect approach to generalized prediction using recursive neural nets. In: E. Simoudis, J. Han, & U. Fayyad. Proceedings of the Second International Conference on Knowledge Discovery and Data Mining. Menlo Park: AAAI Press. Pp. 183-188.
Lange, R., and Houran, J. (2006, April 5-7). Perceived importance of employees’ traits and abilities for performance in hospitality jobs. Paper presented at IOMW 2006, Berkeley, CA.
Lange, R. (1999, October 18). Modeling catastrophes with latent variables in GEMCAT II: Applications to serial murder, paranormal delusions, and organizational product adoption. Presentation to the Chicago Chapter of the American Statistical Association. Chicago, IL.
Lange, R., Jerabek, I., & Houran, J. (2005). Psychometric description of the TRUE Compatibility Test™ – a proprietary online matchmaking system. Dynamical Psychology.
Lange, R., Wilson, G. D., Cousins, J., & Houran, J. (2005). Redefining compatibility: gender differences in the building blocks of relationship satisfaction. Presentation at the 17th Ann. APS Convention. May 26-29, Los Angeles, CA.
Lange, R., Jerabeck, I., & Houran, J. (2004, April 11–12). Building Blocks for Satisfaction in Long-Term Romantic Relationships: Evidence for the Complementarity Hypothesis of Romantic Compatibility. Paper presented at the 2004 Annual meeting of the AERA. San Diego, CA.

Lange, R., Greiff, W. R., Moran, J., and Ferro, L. (2004, May 2-7). A probabilistic Rasch analysis of question answering evaluations. Human Language Technology conference / North American chapter of the Association for Computational Linguistics (NLT/NAACL). Boston, MA.

Lange, R., Greyson, B., & Houran, J. (2004). A Rasch scaling validation of a “core” near-death experience. British Journal of Psychology, 95, 161-177.

Lange, R., McDade, S., and Oliva, T. (2004). The Estimation of a Catastrophe Model of a Cusp Model to Describe the Adoption of Word for Windows. Journal of Product Innovation Management, 21: 15-32.

Lange, R., and Metcalf, L. (2008, June 12-21). Organizers of: Large-Scale Formative Assessment: Reporting Test Results that Are BOTH Psychometrically Sound and Instructionally-Sensitive. Discussant: Prof. James Popham (U of Calif). Session held at the 38th Annual National Conference on Student Assessment, Orlando, FL.

Lange, R., & Hughes, L. (2004, June 23-25). A computer adaptive Version of the Pennsylvania Smell Identification Test (UPSIT). Advances in Health Outcomes Measurement: Exploring the Current State and the Future Applications of Item Response Theory, Item Banks, and Computer-Adaptive Testing. Bethesda, MD.

Lange, R., Thalbourne, M.A., Houran, J., & Lester, D. (2002). Depressive response sets due to gender and culture-based differential item functioning. Personality and Individual Differences, 33, 937-954.
Lange, R., Donathan, C.L., & Hughes, L.F. (2002). Assessing olfactory abilities with the University of Pennsylvania smell identification test: A Rasch scaling approach. Journal of Alzheimer’s Disease, 4, 77-91.
Lange, R. & Houran, J. (2000). Belief vs. fear: Modeling Maher’s attribution theory of delusions as a cusp catastrophe using GEMCAT II, Journal of Nonlinear Dynamics in Psychology and the Life Sciences, 4, 235-254.
Lange, R., McDade, S., & Oliva, T.A. (2001). Technological choice and network externalities: A catastrophe model analysis of firm software adoption for competing operating systems. Structural Change and Economic Dynamics, 12, 39-57.
Lange, R., Oliva, T.A., & McDade, S. (2001). An algorithm for estimating multivariate catastrophe models: GEMCAT II. Studies in Nonlinear Dynamics and Econometrics, 4(3), 137-168. Also appears at snde/vol4/iss3/algorithm1.
Lange, R., & Hughes, L.F. (2001, October 20). Rasch Scaling the UPSIT: Using Smell Recognition to Identify Alzheimer’s Disease, Paper presented on the International Conference on Objective Measurement: Focus on Health Care (ICOM 2001), University of Illinois at Chicago, Chicago, IL
Lange, R., Thalbourne, M. A., Houran, J., & Storm, L. (2000). The revised Transliminality scale: Reliability and validity data from a Rasch Top-Down Purification procedure. Consciousness and Cognition, 9, 591-617.
Lange, R., Oliva, T.A., & McDade, S. (1999, June 13-16). Multivariate catastrophe modeling with GEMCAT II: An organizational product adoption example. Paper presented at the AMA ART Forum. Sante Fe, NM.
Lange, R. & Houran, J. (1999). Scaling the AT-20 using item response theory. Personality and Individual Differences, 26, 467-475.
Lange, R. & Harandi, M.T. (1986). The elements of a distributed knowledge acquisition system. Proceedings of the Sixth International Workshop on Expert Systems and Their Applications. Avignon, France.
Lange, R., Hearn, L., & Kearney, F.W. (1986). The use of knowledge engineering teams as a method for the development of expert systems. In: Sriram, D. and Adey, R. (Eds.). Applications of Artificial Intelligence in Engineering Problems. Boston, MA: Computational Mechanics Publications, pp. 45-54.
Lange, R., & Fishbein, M. (1983). The effects of category differences on belief change and agreement with the source of a persuasive communication. Journal of Personality and Social Psychology, 44, 933-941.
McCutcheon, L.E., Lange, R., & Houran, J. (2002). Conceptualization and measurement of celebrity worship. British Journal of Psychology, 93, 67-87.
Wolfe F., MacIntosh, R., Kreiner, S., Lange, R., Graves, R, Linacre, J.M. (2006) Multiple Significance Tests. Rasch Measurement Transactions, 19:3 p. 1033-44.


Lange, R. (1998-Present). GEMCAT II, V1.0 – V1.3. Delphi 6.0 software for estimating multivariate catastrophe models. Features: Jackknife and bootstrap tests for indicator weights, Pseudo-R2 and Pseudo-F tests for model comparison. A fully operational version of the program and a manual can be downloaded from: ~oliva/cat-theory.htm