RMIT University · FACULTY OF DATA SCIENCE

COSC2670 Chap.7 Experimental Method and Data Science Reporting

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Chapter 7 of 7 · COSC2670

Experimental Method and Data Science Reporting

Define experimental methodology

The course material gives this chapter a concrete anchor: The project examples connect classification questions, cross-validation, accuracy and report structure.

That experimental methodology anchor controls how metric is explained and how technical report is tested in changed practice.

Experimental Method and Data Science Reporting is a quantitative decision problem built from experimental methodology, metric and technical report.

The aim is to turn model output into a report whose claim can be traced to data, method, metric and validation design; a numerical result earns meaning only when the variables, units, assumptions and comparison are all explicit.

Begin with experimental methodology: state what quantity it represents, the scale on which it is measured and the condition under which it changes.

Then map every symbol in the Experimental Method and Data Science Reporting formula checkpoint to experimental methodology before calculation begins.

Next connect metric to the calculation. Show the metric transformation line by line, preserve units and signs, and make any denominator or baseline visible.

A metric calculator output is not a method; the reader must be able to reconstruct why that operation answers the question.

Formula checkpoint: experimental methodology

Classification accuracy
Accuracy=TP+TNTP+TN+FP+FNAccuracy=\frac{TP+TN}{TP+TN+FP+FN}

Accuracy is the fraction of correct predictions, but it can hide failure on a minority class or asymmetric decision cost.

Trace metric

Use technical report to interpret or stress-test the result.

Ask whether the technical report magnitude is plausible, whether a boundary case behaves as expected and which conclusion would reverse if an assumption changed. This is where computation becomes analysis rather than arithmetic.

When the task is to turn model output into a report whose claim can be traced to data, method, metric and validation design, separate inputs supplied by the problem from quantities you derive.

Then report the technical report result in the language of the course and attach the relevant uncertainty, limitation or decision consequence.

Build a representation check before solving. Put experimental methodology, metric and technical report into a small symbol-and-units table, mark which values are observed and which are calculated, and predict the direction of the result before doing arithmetic.

A sign, scale or unit mismatch in experimental methodology then becomes visible at setup instead of being hidden inside a polished final number.

Run one sensitivity test after the baseline answer. Change the input most closely connected to metric, hold the remaining assumptions fixed and recompute only the affected steps. Explain whether the movement in technical report matches the mechanism.

This metric sensitivity shows which assumption controls the conclusion and prevents a single scenario from being presented as universal.

Test with technical report

Use a three-column experimental methodology error log for COSC2670: translation error, calculation error and interpretation error.

Record the exact line where the metric solution first diverged, rewrite that line, and check it with a limiting case or an independent calculation.

Correcting the first failed metric move is more useful than copying the complete solution again.

A complete response should make the task visible before the detail: identify what must be decided, define the relevant terms, connect the evidence to metric, and use technical report to test the result.

The final sentence about technical report should answer the question actually asked rather than merely repeat the topic.

The controlling limit is specific: A high metric does not establish usefulness when the test set, class costs or deployment population do not match the decision.

Keep that technical report limit beside the worked example, because it separates a careful COSC2670 answer from one that sounds confident but claims more than the task or evidence supports.

For revision, retrieve experimental methodology, metric and technical report without notes, explain their relationship aloud, then complete a changed version of the application: turn model output into a report whose claim can be traced to data, method, metric and validation design.

Record the first failed metric reasoning move and repair it before attempting another case.

In this chapter

What this chapter covers

  • 01

    experimental methodology

  • 02

    metric

  • 03

    technical report

  • 04

    Applying experimental methodology

  • 05

    Limits of metric and technical report

Worked example · free

Report a small A/B test honestly

Q [4 marks]. A new search ranking increases click-through from 12.0% to 12.6% in a seven-day experiment, but weekday traffic was unevenly assigned. What belongs in the conclusion?
  • 1Quantify the absolute and relative lift with uncertainty, not just the direction.
  • 1Explain the assignment imbalance and test sensitivity after controlling or stratifying by day.
  • 1Check guardrails such as unsuccessful-search rate and latency.
  • 1Recommend rerun, extension or adoption according to the predeclared decision rule.
The result is provisional: report the 0.6 percentage-point lift, its interval and guardrails, then rerun or extend with balanced assignment before claiming a durable ranking effect.
Sia tip — A data science report should make the strongest surviving claim easy to find and the design limitation impossible to miss.
Glossary

Key terms

experimental methodology
A documented plan connecting question, data, preprocessing, model, validation and evaluation to a reproducible comparison. Use this definition when the task is to turn model output into a report whose claim can be traced to data, method, metric and validation design.
metric
A numerical rule used to evaluate a defined aspect of model performance. Use this definition when the task is to turn model output into a report whose claim can be traced to data, method, metric and validation design.
technical report
An evidence-led account of method, results, limitations and reproducibility information for a specified audience. Use this definition when the task is to turn model output into a report whose claim can be traced to data, method, metric and validation design.
FAQ

Experimental Method and Data Science Reporting FAQ

What is the main task in Experimental Method and Data Science Reporting?

Turn model output into a report whose claim can be traced to data, method, metric and validation design.

How do experimental methodology and metric work together?

Use experimental methodology to establish the object or condition, then use metric to explain how it changes the outcome being analysed.

What must a COSC2670 answer qualify here?

A high metric does not establish usefulness when the test set, class costs or deployment population do not match the decision.

How should I revise Experimental Method and Data Science Reporting?

Retrieve experimental methodology, metric and technical report, apply them to a changed case, and correct the first point where the evidence no longer supports the conclusion.

Study strategy

Assessment move

Reconstruct the relationship among experimental methodology, metric and technical report; complete the chapter application without notes; then test the result against this limit: A high metric does not establish usefulness when the test set, class costs or deployment population do not match the decision.

Working through Experimental Method and Data Science Reporting in COSC2670? Sia is AskSia’s AI Data Science tutor — ask any COSC2670 Experimental Method and Data Science Reporting question and get a clear, step-by-step explanation grounded in how COSC2670 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.

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