Interpretability versus Accuracy in Clinical Machine Learning: Comparing Logistic Regression, SVMs and Random Forests

An MSc Data Science report that recommends the model which did not win on accuracy, and justifies it properly. Three annotated extracts show how to let context override a leaderboard.

Reference
DSC-02
Subject area
Machine Learning
Course level
MSc Data Science
Assessment type
Technical report
Length
c. 2,350 words
Referencing
Harvard (author–date)
Sources cited
12
What this document is

A model answer written by a Global Projects Help mentor, formatted to the conventions of a UK MSc Data Science. It is not a student submission, it was never submitted for assessment anywhere, and no mark was awarded for it — so no grade is quoted on this page. Copyright rests with Global Projects Help.

What this assignment does

The report compares logistic regression, support vector machines and random forests for early breast cancer diagnosis, evaluated by cross-validation with threshold analysis.

Its conclusion is the interesting part: the SVM recorded the best single scores and the report recommends logistic regression anyway, on grounds of interpretability, calibration and the stakes of the decision.

How it is built

Literature, dataset and methodology, results, critical discussion, recommendations. The threshold analysis in the results is what makes the later argument about calibration possible — the structure is load-bearing.

Models are compared on identical folds and identical metrics, so differences are attributable to the model rather than the evaluation.

Annotated extracts

Three passages, each with a note on why it earns marks and what a weaker answer does in the same place — enough to teach the move, not enough to stand in for the assignment.

Extract 1 of 3 Section 5.1 — choosing a model for deployment

Although the SVM recorded the best single scores, logistic regression is arguably the most appropriate model for clinical decision support. Its performance is statistically indistinguishable from the SVM, its coefficients can be inspected directly, and its probabilities are well calibrated, which made the threshold analysis above possible. This is consistent with Rudin's (2019) position that complex models are hard to justify in high-stakes settings when a transparent one performs equally well.

Why this marks well

The report declines to recommend the winner, and every clause of the justification does work: statistically indistinguishable (so nothing is lost), coefficients inspectable (so a clinician can audit it), probabilities calibrated (so the threshold can be tuned to the clinical cost of a miss).

“Statistically indistinguishable” is the load-bearing phrase. Without it the argument would be trading accuracy for interpretability; with it, there is no trade at all, and the recommendation becomes obvious rather than principled-but-costly.

Rudin (2019) is exactly the right citation — her argument is specifically that high-stakes decisions should not use black-box models when interpretable ones match them. The source is load-bearing rather than decorative, and it is cited after the student's own reasoning rather than instead of it.

What a weaker answer does here

A weaker answer reports that the SVM achieved the highest accuracy and recommends it. The analysis is competent and the recommendation ignores everything about the setting in which the model would be used.

Extract 2 of 3 Section 4 — threshold analysis

The SVM achieved the best balance, with the highest cross-validated score. Lowering the classification threshold further increases sensitivity at the cost of specificity.

Why this marks well

Reporting the threshold trade-off rather than a single accuracy figure shows the student understands that a classifier is a family of operating points, not one number.

In a diagnostic setting this is the whole question. A false negative means a missed cancer and a false positive means an unnecessary biopsy — these are not symmetric harms, so the threshold is a clinical decision rather than a statistical default at 0.5.

It also sets up the interpretability argument: only a well-calibrated model lets you move the threshold meaningfully, which is why calibration appears in the recommendation.

What a weaker answer does here

A weaker answer reports accuracy at the default threshold for all three models and compares those numbers. The comparison is valid and answers a question nobody in a clinic would ask.

Extract 3 of 3 Section 3 — methodology

Distance-based and margin-based methods such as the SVM require feature scaling, which was applied within cross-validation folds rather than before splitting.

Why this marks well

Scaling inside the folds rather than before the split is a one-line detail that separates students who understand data leakage from students who have followed a tutorial.

Scaling on the full dataset first lets information from the validation fold influence the training fold, which inflates every score that follows. The report would still have produced plausible numbers — just quietly wrong ones.

Stating it explicitly also tells the marker the comparison is trustworthy, which is what licenses the whole results section.

What a weaker answer does here

A weaker answer normalises the dataset, then splits it, then reports strong results. Nothing looks wrong, the leak is invisible in the output, and every figure in the report is slightly optimistic.

What makes this a strong answer

It recommends against the best-scoring model and makes the case watertight by first establishing that no accuracy is being given up.

It treats classification as a choice of operating point in a setting where the two error types carry very different costs.

The methodology closes the leakage route that would have invalidated the comparison, and says so.

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Using this sample honestly

This is a worked example. It sits in the same place as a worked example in a textbook or a past paper with an examiner’s report attached: read it, take the move, then write your own paragraph without it open in another window.

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  • Sample DSC-02 · Molecular Biology · undergraduate BSc level
    Model answer written by a Global Projects Help mentor · © Global Projects Help
    Published 8 October 2026 · Questions? mia@globalprojectshelp.com