Library · Causal inference & statistics
What Moderation & Interaction Modeling got wrong, from 18 theses
Summary written by a model from the records below: The records describe methodological obstacles encountered when attempting to estimate moderation and interaction models across diverse empirical datasets. Researchers frequently abandoned or pruned interaction terms because of severe multicollinearity, lack of fit improvement compared to main-effects baselines, estimation non-convergence, or measurement model distortions. These records come from graduate theses, 2021 to 2026, each labeled with its degree where the repository states it, and each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Plus 3 problems the authors left open, listed at the end.
Failure modes, by theses reporting them
Select a mode to jump to its records.
Interaction terms fail to improve fit or predictive performance over simpler main effects models
Adding interaction terms to linear, logistic, and mixed models frequently yielded no meaningful improvement in model fit or explained variance compared to simpler additive baselines. In predictive settings, including pairwise interactions even reduced accuracy and added computational cost relative to main effects alone.
Considered and rejected
Considered and rejected: Reverted moderation regression models with sex interaction terms to main effects models only due to nonsignificant increments to R2.
Inside Their Mind: Examining the Relationship Between Visual Mental Imagery and Psychopathic Traits · Carleton University · Master's
Considered and rejected
Considered and rejected: Rejected adding interaction terms to the final multinomial logistic regression model after exploratory analysis showed none significantly improved model fit
The influence of academic and social factors on degree attainment in BSc Sport and Exercise Science · Nottingham · Doctorate
Tried and failed
adding two-way interaction terms to regression models applied to predicting beliefs from psychological features. Outcome: no signal. Reason: interaction terms failed to yield substantive improvements to model fit over simpler additive models
Representations of social and political attitudes, opinions, and facts in the mind and brain · Harvard · PhD
Tried and failed
hierarchical group-lasso for pairwise interactions applied to disease risk prediction from environmental exposures. Outcome: worse than baseline. Reason: interaction terms reduced predictive performance and increased computational cost compared to main effects alone
Cumulative effect of multi-exposures on complex traits and diseases: derivation and applications of the polyexposure risk score · Harvard · PhD
Lost to a baseline
Polynomial proxy with only interaction terms (mean R² = 0.9345) was beaten by the linear proxy with top two interactions (mean R² = 0.9409).
Modeling, optimization, and improvement of the thermal performance of a coaxial closed-loop geothermal system · UT Austin · PhD
Considered and rejected
Considered and rejected: Discarded interaction terms in the main predictors regression model of story certainty in Study 1 after model comparison favored a simpler main-effects model
What Makes For Credible Religious Testimony? Exploring Belief And Skepticism About Others' Religious Experiences · York University · Master's
Considered and rejected
Considered and rejected: Rejected models with interaction terms for logistic regression modeling of P responsiveness, evaluating only simple main effects.
Soil fertility trials on trial for "noise": Statistical implications for soil fertility modeling · Iowa State · PhD
Tried and failed
adding demographic interaction terms to regression models applied to educator survey response prediction. Outcome: no signal. Reason: Interaction terms were statistically insignificant and did not improve model fit over main effects
Measuring Student Agency Conditions · Harvard · PhD
Considered and rejected
Considered and rejected: Rejected adding interaction terms between vowel type and vowel quality in linear mixed models for segmental epenthesis because they did not improve model fit.
Acoustic properties of underlying and derived contrasts in Bedouin Meccan Arabic · Texas Tech · PhD
Interaction terms induce severe multicollinearity that inflates standard errors and distorts estimates
Incorporating interaction terms alongside primary predictors created high multicollinearity that inflated standard errors and diluted established main effects. Researchers were forced to drop interaction terms or test them individually because simultaneous estimation produced uninterpretable slopes and unstable parameters.
Considered and rejected
Considered and rejected: Rejected including interaction terms in the multiple linear regression model due to high multicollinearity among predictor variables (most ps < 0.001).
Tiered Approaches for Educational Equity: Modeling the Determinants of Special Education Disproportionality and Compliance · University of Washington · PhD
Considered and rejected
Considered and rejected: Decided against simultaneously estimating all latent interaction terms in LMS due to multicollinearity, opting to test one interaction model at a time
Revisiting a destination image model in the social media context with the moderator of social distance from a construal level perspective · Iowa State · PhD
Considered and rejected
Considered and rejected: Rejected the original complex regression model (Eq. 3 with simultaneously combined entropy, inverse SEn, and interaction terms) due to uninterpretable slopes and severe multicollinearity.
Measuring Dynamic Team Reorganization and Interdependency in Response to Uncertainty · Georgia Tech · PhD
Model complexity with interaction terms causes estimation non-convergence and imprecision
Specifying full interaction models exceeded sample statistical power and led to estimation non-convergence in multiple imputation equations and mixed-effects regressions. In discrete choice contexts, insufficient data rendered interaction parameters imprecisely estimated with weak statistical significance.
Tried and failed
conditional logit with full interaction terms applied to discrete choice preference estimation. Outcome: data insufficient. Reason: interaction terms were imprecisely estimated with weak statistical significance, limiting interpretability
Considered and rejected
Considered and rejected: Rejected including interaction terms in multiple imputation equations due to non-convergence
Labour induction in Nova Scotia: What has contributed to rising rates? · Dalhousie · Master's
Tried and failed
mixed-effects logistic regression with interaction terms applied to small annotated corpus data. Outcome: did not converge. Reason: Model complexity with interaction terms exceeded the statistical power of the dataset size.
Aspectual predictors of mood selection in specialized imperative verbal forms in Gothic · Iowa State · Master's
Interaction modeling conflicts with measurement models or fails structural prerequisites
Latent interaction terms were excluded from baseline confirmatory factor analysis models because they biased measurement model fit estimates. In other cases, researchers abandoned complex moderation and moderated-mediation analyses when prerequisite bivariate correlations or preliminary hierarchical stages were non-significant.
Considered and rejected
Considered and rejected: Full moderated-mediation path analysis via PROCESS macro was abandoned because interaction terms in hierarchical regressions were non-significant
Exploring the Effect of Anti-Bisexual Experiences on Perceived Stress and Eudaimonic Well-Being in Bisexual Individuals: The Role of Self-Compassion and Outness · University at Buffalo · PhD
Considered and rejected
Considered and rejected: Rejected moderation analysis due to absence of significant correlations between Psychological Flexibility and Birth Satisfaction/Expectations
The role of psychological flexibility in birth experience for first-time mothers: a mixed methods study · Nottingham · Doctorate
Considered and rejected
Considered and rejected: Excluded latent interaction terms from baseline measurement model CFA because interactions bias model fit estimates.
Outcomes of Interpersonal Felt Distrust in the Workplace: An Identity Threat Perspective · York University · PhD
Left open by the authors
Problems the authors named and did not get to.
Left open
Estimate regression models including interaction terms between distinct management dimensions like goal setting and feedback to assess organizational reform heterogeneity. Blocker: Requires the proprietary organizational management survey and clinical performance dataset used in the dissertation
How do health care organizations’ characteristics affect the effectiveness of service delivery reforms? · Harvard · PhD
Left open
Estimate interaction terms for respondent occupation in the conditional logit model to evaluate its effect on willingness-to-pay for offshore wind co-location. Blocker: Requires the private survey response microdata containing respondent occupations.
Opportunity Between the Turbines: A Willingness-to-Pay Experiment Regarding Co-Location Activities with the Coastal Virginia Offshore Wind Farm · Virginia Tech · Master's
Left open
Perform a meta-analytic moderation analysis testing whether age or game type moderates the predictive validity of deliberate practice versus cognitive ability. Blocker: None
What Causes High Achievement? An Investigation of "Talent" and Its Alternatives · Penn · PhD
Who has worked on this
Authors of the public theses cited on this page, most-cited first.
- Ben Shryock · Harvard · 2026
Money Making Matching Markets: Analyzing Student-Athlete Sorting and Welfare Outcomes under NCAA NIL-Policy - Nicholas Balisciano · Harvard · PhD · 2026
Measuring Student Agency Conditions - David Alan Ponce Grimm · Georgia Tech · PhD · 2025
Measuring Dynamic Team Reorganization and Interdependency in Response to Uncertainty - Graziela Farias Martelli · York University · Master's · 2025
What Makes For Credible Religious Testimony? Exploring Belief And Skepticism About Others' Religious Experiences - Alex Mitchell Cleveringa · Iowa State · PhD · 2025
Soil fertility trials on trial for "noise": Statistical implications for soil fertility modeling - Mohammed Alahmadi · Texas Tech · PhD · 2025
Acoustic properties of underlying and derived contrasts in Bedouin Meccan Arabic - Iryna Kalynychenko · York University · PhD · 2025
Outcomes of Interpersonal Felt Distrust in the Workplace: An Identity Threat Perspective - Roshni Sohail · Carleton University · Master's · 2024
Inside Their Mind: Examining the Relationship Between Visual Mental Imagery and Psychopathic Traits - Rachelle Entz · Dalhousie · Master's · 2024
Labour induction in Nova Scotia: What has contributed to rising rates? - Sian Hsiang-Te Tsuei · Harvard · PhD · 2023
How do health care organizations’ characteristics affect the effectiveness of service delivery reforms? - Joshua Satya Cetron · Harvard · PhD · 2023
Representations of social and political attitudes, opinions, and facts in the mind and brain - Daniel Aaron Southwick · Penn · PhD · 2023
What Causes High Achievement? An Investigation of "Talent" and Its Alternatives
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