Our Research Team

A broad, deep portfolio of expertise and experience benefits our clients and company alike.
Tia Sukin, Ed.D.

Tia Sukin, Ed.D.

Director of Research for Psychometric Services

Tia Sukin serves as the Director of Research for Psychometric Services at Pacific Metrics. She manages the psychometric direction of our online testing programs; and leads the Psychometric team in overseeing a research agenda, supervising test development efforts, and supporting the decision making process of clients and business partners on relevant projects.

Past endeavors have provided Dr. Sukin with valuable experience working with high-stakes assessment programs like Defense Language Proficiency Tests, the National Assessment of Educational Progress, and state accountability programs for special populations.

Her research interests include item response theory, test equating methods, item parameter drift detection, generalizability theory applications, and validity studies. She aims to enhance the valid use of test data and assessment literacy for various stakeholders.

Wim van der Linden, Ph.D.

Wim van der Linden, Ph.D.

Distinguished Scientist & Director of Research Innovation

Dr. Wim J. van der Linden is Distinguished Scientist and Director of Research Innovation at Pacific Metrics. He is also a Professor Emeritus of Measurement and Data Analysis at the University of Twente, Netherlands. He has published over 300 journal articles, authored a book Linear Models for Optimal Test Design, and edited several volumes on test theory, including the three-volume Handbook of Item Response Theory, to be published by Chapman & Hall/CRC in spring 2016. Dr. van der Linden a past president of the Psychometric Society and NCME, a recipient of the NCME and ATP career achievement awards as well as the AERA E. F. Lindquist award, and holds a honorary doctorate from the University of Umeå, Sweden. His research interests include item response theory, adaptive testing, optimal test assembly, parameter linking, test equating, and response-time modeling and applications.

W. Alan Nicewander, Ph.D.

W. Alan Nicewander, Ph.D.

Chief Psychometrician

Dr. Nicewander, a practicing expert in educational and psychological measurement, has achieved recognition for his work in using item response theory (IRT) to solve applied testing problems. He advises on large-scale testing issues, conducts research and technical studies for the company’s contracts and product line, and implements psychometric aspects of statewide assessment programs. Most recently, he was been engaged in developing growth measurement and vertical scaling methodology.

He has written dozens of journal articles and is a former professor and chairman of the Psychology Department at the University of Oklahoma. He previously served as director of statistical research for ACT, Inc., and head of the Department of Defense Personnel Testing Division. Dr. Nicewander holds a Ph.D. in Psychometrics and Applied Statistics from Purdue University.

Sandip Sinharay, Ph.D.

Sandip Sinharay, Ph.D.

Chief Statistician

As Chief Statistician, Dr. Sinharay provides statistical support for programs and special projects and leads efforts to secure funding in support of research and development in educational assessment.

He has received four awards from the National Council on Measurement in Education, two ETS Presidential Awards, and an ETS Service Scientist Award. Dr. Sinharay is the co-editor of two published volumes and the author of more than 75 articles in peer-reviewed statistics and psychometrics journals and edited books.

Susan Lottridge, Ph.D.

Susan Lottridge, Ph.D.

Director of Machine Scoring and Psychomectric Tools

Dr. Lottridge leads automated scoring efforts and manages operational scoring, monitoring, and reporting.  She ensures that proper procedures are followed with respect to engine functioning, versioning, and quality assurance. Since 2007 she has led the automated scoring effort for Louisiana’s end-of-course high stakes assessment program developed by Pacific Metrics and previously led the automated scoring effort for Louisiana’s PASS assessment program.

Dr. Lottridge holds a Ph.D. in Assessment and Measurement from James Madison University, an M.S. in Computer Science and an M.A. in Mathematics from University of Wisconsin, Madison, and a B.A. in Mathematics from the University of St. Thomas.

Michelle Barrett, Ph.D.

Michelle Barrett, Ph.D.

Director of Assessment Technology

Michelle Barrett is the Director of Assessment Technology at Pacific Metrics, responsible for the design, engineering, and development of industry leading assessment technology solutions. Previously, she worked for CTB McGraw-Hill where she led efforts on psychometric utilities, optimal test design, computer adaptive testing engines, and artificial intelligence engine training and validation systems. Ms. Barrett also worked as a senior consultant in the assessment division at the Colorado Department of Education. She holds a bachelor’s degree from Stanford University, a master’s degree from Harvard Graduate School of Education, and a graduate certificate in large scale assessment from the University of Maryland. She received her PhD in research methods, data analysis, and measurement from University of Twente, Netherlands, in 2015.

Daniel Lewis, Ph.D.

Daniel Lewis, Ph.D.

Principal Research Scientist

Dr. Lewis supports the design and development of new products, methods and serves in Pacific Metric’s product group. After teaching elementary school, he taught mathematics at Kent State University, where he earned his master’s degree in Pure Mathematics. Dr. Lewis completed his doctorate in Educational Measurement and taught educational research methods as an Associate Faculty member of the Graduate School of Education at Kent State University. He also served as Chief Research Advisor at McGraw-Hill Education CTB.

Dr. Lewis and Pacific Metrics co-founder Dr. Howard Mitzel authored the Bookmark Standard-Setting Procedure, now the predominant method for setting performance standards in the United States. Dr. Lewis’ subsequent research was foundational to the area of measurement now described as Vertically Moderated Standard Setting.  His current research interests include test report design, standard setting, growth models, and assessment policy.

Furong Gao, Ph.D.

Furong Gao, Ph.D.

Sr. Research Statistician

Dr. Gao provides technical leadership and psychometric guidance on educational measurement product development, design and implementation of research studies.

She has worked as a senior research statistician and a research manager at CTB/McGraw-Hill Education and was the lead research scientist on developing the TerraNovaTM achievement assessments.  As a senior statistician in the Web Search division at Yahoo! Inc., Dr. Gao conducted statistical data analyses on user intent and behavior, relevancy of search results, A/B bucket testing on search engine performance, and provided business insights based on data findings for search algorithm optimization.

Scott Wood, Ph.D.

Scott Wood, Ph.D.

Associate Director of Machine Scoring

Dr. Wood leads numerous projects around research and development of scoring engines for Pacific Metrics, including psychometric training, validation, monitoring, and statistical analysis.

As a graduate student, Dr. Wood worked for Iowa Testing Programs and the Department of Statistics and Actuarial Science at the University of Iowa. He also served as a statistician for a variety of freelance projects across multiple disciplines.

Dr. Wood holds a Ph.D. in Educational Measurement and Statistics and an M.S. in Statistics from the University of Iowa, as well as a B.A. in Mathematics and a B.A. in Quantitative Methods/Computer Science from the University of St. Thomas (MN).

Teresa E. Walker, Ph.D.

Teresa E. Walker, Ph.D.

Research Scientist, Scoring

Dr. Walker provides thought leadership in all aspects of scoring across multiple projects at Pacific Metrics. As part of the automated scoring (AS) team, she serves as the liaison between the AS staff, programs, and clients to formulate policies around the use of AS, as well as coordinates the technical integration of the AS engine with test delivery platforms and monitoring of AS during testing. Since 2010, she has served as the liaison with the handscoring vendor on one of Pacific Metrics’ large-scale state assessment contracts. In that role, she is responsible for developing and maintaining process documentation and technical specifications, as well as managing scoring-related activities, timelines, and milestones. She also oversees the vendor’s adherence to proper scoring protocols, including using statistical information to monitor the vendor’s readers during operational administrations. Moreover, Dr. Walker consults with multiple departments to ensure a comprehensive approach to scoring, including supporting test development and item-writing activities by providing scoring-based information for item writing, evaluation, and selection. In addition to the scoring work, Dr. Walker provides support to Research and Test Development by preparing for and co-facilitating standard setting workshops and writing technical reports and memoranda.
Dr. Walker received her Ph.D. and M.S. in cognitive psychology from the University of California, Santa Cruz. She also holds a B.A. from Christopher Newport University in Newport News, Virginia.

Minh Duong, Ph.D.

Minh Duong, Ph.D.

Senior Psychometrician

Dr. Duong provides psychometric analysis and equating procedures; leveraging his deep knowledge and experience in test design, test form development, item analyses, calibration, equating, scaling, technical deliverables, and technical reports.Dr.

Duong is fluent in several programming languages including SAS, and has extensive experience in designing and conducting research in test equating, IRT parameter estimation, and test validity. He holds a Ph.D. in Measurement and Quantitative Methods from Michigan State University, an M.S. in Science Education from Simon Fraser University, and a B.S. in Physics from Cantho University in Vietnam.

Vincent Kieftenbeld, Ph.D.

Vincent Kieftenbeld, Ph.D.

Senior Research Scientist

Vincent Kieftenbeld is a senior research scientist at Pacific Metrics, where he focuses on building innovative assessment solutions that combine technology and psychometrics.

Previously, he conducted research and development on automated scoring at McGraw-Hill Education CTB. Vincent was responsible for several research projects that were part of the Smarter Balanced automated scoring research studies.

He holds a master’s degrees in mathematics and secondary education (mathematics) from the University of Amsterdam, Netherlands, and a PhD in mathematics from the University of North Texas.

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