University of Melbourne · FACULTY OF COMPUTER SCIENCE

COMP90089 Chap.2 Clinical Data Sources, Types and Missingness

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Chapter 2 of 9 · COMP90089

Clinical Data Sources, Types and Missingness

Define electronic health record

The course material gives this chapter a concrete anchor: Lecture 4 details clinical data types; MIMIC access pages expose practical table and governance constraints.

That electronic health record anchor controls how clinical data type is explained and how informative missingness is tested in changed practice.

Clinical Data Sources, Types and Missingness is a quantitative decision problem built from electronic health record, clinical data type and informative missingness.

The aim is to select and align data types while preserving time, unit and care-process meaning; a numerical result earns meaning only when the variables, units, assumptions and comparison are all explicit.

Begin with electronic health record: 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 Clinical Data Sources, Types and Missingness formula checkpoint to electronic health record before calculation begins.

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

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

Formula checkpoint: electronic health record

Missingness rate
mj=1N∑i=1N1(xij missing)m_j=\frac{1}{N}\sum_{i=1}^{N}\mathbf{1}(x_{ij}\ \mathrm{missing})

The rate counts absent values for feature j but does not identify why they are absent.

Trace clinical data type

Use informative missingness to interpret or stress-test the result.

Ask whether the informative missingness 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 select and align data types while preserving time, unit and care-process meaning, separate inputs supplied by the problem from quantities you derive.

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

Build a representation check before solving.

Put electronic health record, clinical data type and informative missingness 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 electronic health record 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 clinical data type, hold the remaining assumptions fixed and recompute only the affected steps. Explain whether the movement in informative missingness matches the mechanism.

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

Test with informative missingness

Use a three-column electronic health record error log for COMP90089: translation error, calculation error and interpretation error.

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

Correcting the first failed clinical data type 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 clinical data type, and use informative missingness to test the result.

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

The controlling limit is specific: a missing test can mean not needed, not ordered, inaccessible or not recorded.

Keep that informative missingness limit beside the worked example, because it separates a careful COMP90089 answer from one that sounds confident but claims more than the task or evidence supports.

For revision, retrieve electronic health record, clinical data type and informative missingness without notes, explain their relationship aloud, then complete a changed version of the application: select and align data types while preserving time, unit and care-process meaning.

Record the first failed clinical data type reasoning move and repair it before attempting another case.

In this chapter

What this chapter covers

  • 01

    Electronic health record

  • 02

    Clinical data type

  • 03

    Informative missingness

  • 04

    Applying electronic health record

  • 05

    Limits of clinical data type and informative missingness

Worked example · free

Measure missingness

Q [4 marks]. AskSia-authored practice. In a cohort of 2,000 stays, lactate is absent in 1,500. Calculate the missingness rate and interpret cautiously. The step allocation is an independently authored practice structure, not an official marking scheme.
  • 1Divide 1,500 by 2,000.
  • 1Report 75% missingness.
  • 1Ask why testing was ordered.
  • 1Avoid treating imputation as causal repair.
Lactate is missing for 75% of stays. The pattern may reflect clinical selection and severity, so imputation alone cannot recover an unbiased measurement process.
Sia tip — A null is a data event with provenance, not an empty cell waiting for a mean.
Glossary

Key terms

Electronic health record
Longitudinal digital record produced through care, administration and documentation processes. This chapter uses the concept when students select and align data types while preserving time, unit and care-process meaning. Use this definition when the task is to select and align data types while preserving time, unit and care-process meaning.
Clinical data type
Representation such as coded event, laboratory value, note, image, waveform or medication order. It helps explain the reasoning required to select and align data types while preserving time, unit and care-process meaning. Use this definition when the task is to select and align data types while preserving time, unit and care-process meaning.
Informative missingness
Absence whose probability depends on patient state or care process and can carry signal or bias. Its limit matters because a missing test can mean not needed, not ordered, inaccessible or not recorded. Use this definition when the task is to select and align data types while preserving time, unit and care-process meaning.
FAQ

Clinical Data Sources, Types and Missingness FAQ

Which criteria should govern an attempt to select and align data types while preserving time, unit and care-process meaning?

Select and align data types while preserving time, unit and care-process meaning. Lecture 4 details clinical data types; MIMIC access pages expose practical table and governance constraints.

Can a missing test mean not needed, not ordered, inaccessible or not recorded?

A missing test can mean not needed, not ordered, inaccessible or not recorded. Representation such as coded event, laboratory value, note, image, waveform or medication order. It helps explain the reasoning required to select and align data types while preserving time, unit and care-process meaning.

If the hospital's ordering protocol changed, how should a student predict which feature distribution shifts?

Lactate is missing for 75% of stays. The pattern may reflect clinical selection and severity, so imputation alone cannot recover an unbiased measurement process. A missing test can mean not needed, not ordered, inaccessible or not recorded.

Study strategy

Assessment move

Reconstruct the relationship among electronic health record, clinical data type and informative missingness; complete the chapter application without notes; then test the result against this limit: a missing test can mean not needed, not ordered, inaccessible or not recorded.

Working through Clinical Data Sources, Types and Missingness in COMP90089? Sia is AskSia’s AI Computer Science tutor — ask any COMP90089 Clinical Data Sources, Types and Missingness question and get a clear, step-by-step explanation grounded in how COMP90089 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.

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