Challenges and Solutions for Data Analysis in an Adult Lifespan Study of over 100,000 Online Cognitive Test Completions
Bibliographic record
Abstract
Note: This pre-print includes the accepted version of a manuscript that was published in Sage Research Methods: Doing Research Online in 2022 (https://doi.org/10.4135/9781529600). In this case study, I describe methodological insights from data analysis of an online adult lifespan dataset (over 100,000 completions, ages 15-100). The data were used to study cross-sectional age differences in cognitive performance. I cover the steps of data analysis for large-scale web-based data, namely data cleaning, analysis, and visualization techniques. In each step, I describe the unique challenges that face analysis of data collected online, and potential solutions to address them, by drawing on practical lessons and examples from this study. First, I address how to identify problematic recordings such as technical issues (incomplete data, multiple completions by the same person, etc.), unreliable self-reported demographic information (age), and cognitive task outliers (accuracy, response times). I propose rigorous data cleaning as an essential first step to ensure that analytical conclusions are reliable and unbiased. Next, I demonstrate data visualization techniques that are better suited to large online datasets than more conventional techniques (e.g., density plots or locally weighted scatterplot smoothing instead of dot-plots or linear regression). Lastly, I cover the limitations of significance testing in large online datasets, and the value of complementary approaches such as data visualization, effect size estimation, and use of parsimony criteria. I also discuss more sophisticated analysis options enabled by large online datasets, such as non-linear regression, model comparison and selection, data resampling, and addition of covariates.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.227 | 0.519 |
| Meta-epidemiology (narrow) | 0.001 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.003 |
| Bibliometrics | 0.008 | 0.013 |
| Science and technology studies | 0.005 | 0.006 |
| Scholarly communication | 0.009 | 0.009 |
| Open science | 0.005 | 0.009 |
| Research integrity | 0.004 | 0.007 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".