SCIENCE · INVESTIGATE AND EXPLAIN

Audit the record frame before using a resistance percentage

Resistance surveillance can inform stewardship only when the population, sampling, definitions and time frame are clear. A percentage from one selected set of records is not automatically a population prevalence or a rule for an individual’s treatment. Stewardship includes using evidence responsibly and avoiding unsupported antimicrobial use, not selecting a drug from an arbitrary classroom table.

Learning outcome: Compare unique and entry-weighted fractions while changing duplicates only. Then change sample mixture and explain why a standardized comparison is not the same as evidence of representativeness.

Starting recap

Bound control and susceptibility interpretations by measurement, heterogeneity, source frames and unused evidence; distinguish resistance, tolerance and nonrecovery without operational or clinical claims.

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Try

At h=0.5, d=2, there are 50 low and 50 high unique records but 150 reported entries. State-positive entries are 5+40=45, giving reported fraction 0.3. The unique-record fraction is(5+20)/100=0.25; repeated high records explain the difference.

Open the experiment

Predict

Can a reported percentage rise without a change in either stratum-specific state fraction?

Your prediction and reason

Experiment

Compare unique and entry-weighted fractions while changing duplicates only. Then change sample mixture and explain why a standardized comparison is not the same as evidence of representativeness.

Compare surveillance percentages without changing the denominator silently

Worked teaching model · synthetic values · Original unique records100, low/high state fractions0.1/0.4. Sampling mixture a; high records appear b times while low once. Record-weighted fraction differs from deduplicated unique-record fraction. No actual antibiogram or prescribing rule.

Fraction of sampled records from stratum high: 0.5 fraction Duplicate copies per high-stratum record: 2 copies

Reset keeps your prediction, captures and practice history.

Duplicate records and sampling composition can change a reported percentage without changing either stratum-specific state fraction.

Original unique records100, low/high state fractions0.1/0.4. Sampling mixture a; high records appear b times while low once. Record-weighted fraction differs from deduplicated unique-record fraction. No actual antibiogram or prescribing rule.

Original conditional model quantities
Quantity	Value	Unit
Unique-record state fraction	0.2500000	fraction
Reported entries including duplicates	150	entries
State-positive reported entries	45	entries
Entry-weighted state fraction	0.3000000	fraction
Fixed half/half standardized unique fraction	0.2500000	fraction

Supplied fictional records only. No control-process operation, chemical preparation, culture, resistance generation or clinical interpretation is requested.

Duplicate records and sampling composition can change a reported percentage without changing either stratum-specific state fraction.

Observation to attach to a capture

Captures preserve recipes and replay their calculated results. They are synthetic model evidence, not physical measurements.

Understand

Define the evidence boundary

Connect mechanism and measurement

The original record has 100 unique units divided into low/high strata with fixed state fractions 0.1/0.4. High-stratum fraction h changes the sampled mixture. Each high-stratum unit appears d times in the reported file while each low unit appears once. The unique-record fraction is 0.1(1−h)+0.4h; the entry-weighted fraction divides 10(1−h)+40hd by 100(1−h)+100hd.

Duplicates can increase the weight of a stratum without adding independent information. Deduplication and an explicit target mixture answer different questions: removing repeat entries restores this unique-record sample, while half/half standardization yields 0.25 regardless of the original sample mixture. Neither step establishes that the unique sample represents all communities or patients.

Actual interpretation also needs source identity, laboratory definitions, uncertainty and an appropriate qualified decision framework. No actual antibiogram, organism-agent combination, prescribing threshold or treatment choice appears here. The task is to audit evidence before making a stronger claim, not to replace professional guidance.

Reconstruct the original record

Predict and investigate

Predict first: Can a reported percentage rise without a change in either stratum-specific state fraction?

Compare unique and entry-weighted fractions while changing duplicates only. Then change sample mixture and explain why a standardized comparison is not the same as evidence of representativeness.

Defend a changed case

Apply the mechanism to a changed boundary

Use h=0.2, d=3. Find unique fraction, total entries and entry-weighted fraction.

Retain the first response, units, uncertainty and any prior feedback exposure in the notebook before comparing this public explanation.

Compare a worked response

Unique fraction 0.16, total entries 80+60=140 and state-positive entries 8+24=32. Entry-weighted fraction 32/140=8/35≈0.228571. Half/half standardized unique fraction remains 0.25, a different declared target.

Retain bounded evidence

Preserve the original source, first response, units, uncertainty and feedback exposure in the Microbiology evidence workspace. All numerical records are fictional. No culture, control-process execution, chemical preparation, genetic manipulation, resistance generation, participant testing or clinical decision is requested. Actual practical and independent learner competence remain separate.

Primary mechanism or evidence context, checked 31 October 2026. Original teaching and supplied records; no source operating procedures copied.

Apply

Public practice checks a specific claim. It does not establish independent mastery.

Use h=0.2, d=3. Find unique fraction, total entries and entry-weighted fraction.

Your explanation and limitations

Continue

Completion requires a saved prediction, at least one capture and a reflection. Presence checks do not grade your reasoning.

Skipping retains experiments and awards no mastery.

Previous: Separate inherited-state frequency from expression per carrier Next: Choose discriminating evidence without mistaking fit for truth

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