Infection-control CER
This page has four parts, in the order you use them. Part 1 is what you need to know. Part 2 says what to do, in plain English. Part 3 shows the work done once on a case that is not yours. Part 4 is your own work and where to turn it in.
Open your materials, follow the steps, then turn in your work.
Students write a CER recommending an infection-control plan supported by chain-of-infection evidence.
Check you have the right sheet: the top of it prints today's portal day, Infection-control CER. The PLTW activity itself is in myPLTW and is not posted here.
Optional: listen or watch a unit review▸
Part 1 of 4 · Background and definitions▸
💡 Big idea: An infection-control CER earns trust because it names the mechanism, predicts an outcome, and states its assumptions, so anyone can test whether the control actually works.
- • The highest-priority control is the one that breaks the most vulnerable or most accessible link in the chain.
- • Predicting the expected effect requires reasoning from mechanism, not just assertion.
- • Every control plan has assumptions; stating them is the difference between a recommendation and a claim.
You must locate the single weakest link in a specific case before prescribing a control, because a targeted fix aimed at the real weak point works while a general hygiene tip cannot be tested or aimed.
An infection-control CER earns trust because it names the mechanism, predicts an outcome, and states its assumptions, so anyone can test whether the control actually works.
Driving question: For your case, can you write a claim that names one priority control, explains the mechanism by which it cuts infection, and predicts how much risk drops?
What you already know: You must locate the single weakest link in a specific case before prescribing a control, because a targeted fix aimed at the real weak point works while a general hygiene tip cannot be tested or aimed.
New idea: An infection-control CER earns trust because it names the mechanism, predicts an outcome, and states its assumptions, so anyone can test whether the control actually works.
- Observe or measure the relevant feature in infection-control CER.
- Organize the observation with a stable evidence ID.
- Apply this rule: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: For your case, can you write a claim that names one priority control, explains the mechanism by which it cuts infection, and predicts how much risk drops?
What the evidence supports: E1 to E3 and the figure support the daily take-home when the response meets the stated success criteria.
What it cannot prove: The package does not support claims beyond this lesson's or any real patient diagnosis.
- • nosocomial: Describes an infection that a patient catches while in a hospital or healthcare setting rather than bringing it in from outside.
- • : A microorganism such as a bacterium, virus, fungus, or parasite that can cause disease in its host.
- • vector: Two senses, set by the lesson. In infection control, a living , usually an insect such as a mosquito or a tick, that moves a from one host to the next. In genetics, a or virus engineered to carry into a cell.
- • reservoir: A living host or environment where a normally lives and multiplies, serving as the source from which infections spread.
- • : The passing of a disease-causing agent from one host to another, by routes such as contact, droplets, contaminated objects, or vectors.
- • : The body's coordinated defense against a harmful invader, in which immune cells recognize, attack, and remember the threat.
- • : Personal protective equipment, the gear like gloves, goggles, lab coats, and masks worn to shield the body from chemical, biological, or physical hazards.
- • : Describing techniques that keep an area free of harmful microbes so cultures and patients are not contaminated.
Use it now: Choose one decision option. Cite E1 and E3, then explain how the rule connects the evidence to your choice. This is thinking practice for the one turn-in named under Turn in, not a second submission.
Go further, optional: The source links below are optional enrichment. Every fact required for today's local evidence decision appears in this lesson package.
Infection prevention targets links that allow an infectious agent to reach a susceptible host, and the selected control must match the route and evidence in the case.
Limit: The classroom chain model simplifies host, , environment, timing, and implementation factors and cannot establish a real outbreak source.
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
Limit: A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
Write a CER with a clear control claim and chain-based evidence.
Limit: E3 defines the classroom product or success criterion. It is not independent scientific evidence and cannot justify a clinical or causal claim.
Today's decision · Simulated classroom evidence scenario
Your role: biomedical team member
Decision: Your team must decide what the evidence from infection-control CER supports before submitting the claim-evidence-reasoning response named on today's page.
- • Hold the predicted risk drop until we know this unit's infection rate before the control was put in place.
- • Write reasoning that explains the mechanism by which breaking your chosen link cuts infection, not a longer claim.
- • Restate your control claim in fuller sentences for the reasoning section, since that is what reasoning is meant to do.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Use it inside the one turn-in named under Turn in; it is not a separate submission.
Claim ceiling: Today's evidence supports a classroom claim about infection-control CER. It cannot prove causation, diagnose a real patient, or justify action outside this room.
Reason for review: Your team must decide what the evidence from infection-control CER supports before submitting the claim-evidence-reasoning response named on today's page.
Context: A scientific recommendation names a mechanism, predicts a result, and states its own assumptions, so it can be tested and trusted.
- • T1: State a claim naming the highest-priority control for the scenario.
- • T2: Cite evidence from the chain of infection and the patient context.
- • T3: Explain reasoning that links the control to interrupted .
- • T4: Predict the expected effect on infection risk if the control is applied.
- • T5: Identify assumptions and limitations affecting the recommendation.
- • E1: Infection prevention targets links that allow an infectious agent to reach a susceptible host, and the selected control must match the route and evidence in the case.
- • E2: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
- • E3: Write a CER with a clear control claim and chain-based evidence.
Measurements: Use only the measurements, units, graph, or counts supplied in today's task. No additional patient measurement is implied.
Figure finding: A stacked claim-evidence-reasoning skeleton: a claim box, an evidence box with three lines, an accent arrow labeled mechanism from evidence to reasoning, a reasoning box, a dashed prediction box and an assumptions and limitations box.
Uncertainty: This is a composite classroom scenario. Missing history, measurements, or confirmation tests remain unknown and limit the conclusion.
Students often think the reasoning section just restates the claim in more words. The trap: Reasoning is not repetition, because a claim tells you what to do while reasoning explains the mechanism of why breaking that link cuts infection. If your reasoning could be deleted without losing information, you wrote a restatement, not a mechanism.
- CER:
- Claim, Evidence, Reasoning: make a claim, back it with evidence, explain your reasoning.
- SOP:
- Standard Operating Procedure, the exact steps to follow (especially in a lab).
- Tracker:
- Your PLTW progress log where you record completed evidence.
- myPLTW:
- The PLTW course site where you do the online activities. Find it in Clever with your Microsoft sign-in, right next to Schoology.
Tap the speaker to hear a term. Add two of these to your notebook glossary with a definition and an example in your own words.
Pick just 2 or 3 words from today and make them yours: write what each one means in your own words, name the context clue or evidence that helped, then give one example from what you actually did in Infection-control CER. Try your own words first; the glossary is there if you get stuck. This is voluntary and counts as extra credit, so keep it short.
Saved on this device. Show Mr. Mendoza or add these to your notebook glossary to claim the extra credit.
Part 2 of 4 · Directions in plain English▸
2.1 Open your materials
2.2 Start the work
State a claim naming the highest-priority control for the scenario.
Show all 5 required steps
- State a claim naming the highest-priority control for the scenario.
- Cite evidence from the chain of infection and the patient context.
- Explain reasoning that links the control to interrupted transmission.
- Predict the expected effect on infection risk if the control is applied.
- Identify assumptions and limitations affecting the recommendation.
Lost your place? A full CER has claim, evidence, reasoning, prediction, and limitations. Find which of the five is missing from your draft and resume at that step; most stall at reasoning, which is step 3.
- 0-8 minReview your case analysis; confirm the highest-priority chain link and proposed control.
- 8-20 minWrite the claim: one sentence naming the highest-priority infection-control intervention.
- 20-42 minWrite evidence: cite chain link, patient context, and -route data.
- 42-60 minWrite reasoning: link each evidence point to the claim and predict the expected effect.
- 60-72 minAdd assumptions and limitations section.
- 72-80 min: confirm claim is specific, prediction is present, limitation is stated.
- • In the infection-control case you found the weakest link; today you write the formal argument for why your control is the right choice.
- • The prediction section is what separates a CER from a case summary: you must say what you expect to happen.
- • the biotechnology part of your end-of-course WebXam tests causal reasoning, not just factual recall.
- • Name your assumption explicitly: if it turns out to be wrong, your recommendation may also be wrong.
PLTW connection and today's work
In myPLTW, open Lesson 3.1 Nosocomial Nightmare and go to Activity 3.1.4 Evidence Evaluation. Use it as the scaffold for your CER.
Today's stopping point: Platform prompts done in first 15 minutes; full CER complete before end of period.
PLTW activity titles identify the course connection. If your account will not open, use the posted materials for today and tell Mr. Mendoza. Do not mark an online activity complete unless you completed it.
Course connection
- Activity 3.1.4 Evidence Evaluation
Use the turn-in directions in Part 4 of this page. Do not create a second submission unless your teacher asks for one.
Show another explanation or a smaller first step
Need help? Choose a starting point
Part 3 of 4 · Worked example▸
This is a parallel case, not your own. Read it for the order of the work, then do your own in Part 4.
Claim: The highest-priority control for this cafeteria outbreak is a stay-home rule that keeps any food handler with vomiting or diarrhea out of the kitchen until 48 hours after symptoms stop.
Evidence: The chain trace showed norovirus spreading through the reservoir link, when one food handler who worked while sick shed virus onto serving utensils and ready-to-eat trays. From there the mode of transmission was fecal-oral contact through contaminated food, and the susceptible hosts were students whose only shared exposure was the lunch line. Handwashing and surface cleaning matter, but the sick worker was the source feeding the whole chain, and staff scheduling is a link the school controls directly.
Reasoning: Removing an infected reservoir shuts off the supply of new agent before it can ever reach a portal of entry. If no sick handler touches the food, there is nothing for handwashing or cleaning to catch up on later, so this breaks the chain at its source rather than trying to intercept virus that has already spread across trays and hands. Norovirus is shed in very high amounts and stays contagious for about two days after symptoms end, so a 48-hour exclusion targets the exact window when a returning worker is still a reservoir.
Expected effect: If the stay-home rule is enforced, foodborne transmission events of this type should drop sharply, because the single pathway in this scenario ran through food touched by an infected handler.
Assumptions and limitations: I assume the sick handler was the true source and that workers will report symptoms honestly rather than come in for a paycheck. If the virus actually entered through a contaminated food shipment or a sick student touching a shared drink station, exclusion alone would not be enough, and we would need to target a different link such as the mode of transmission or the portal of entry.
This model shows the level of evidence and organization needed to complete: Models the infection-control argument on a different scenario (a norovirus outbreak in a school cafeteria): a claim, evidence, and reasoning paragraph that names the highest-priority control, ties it to a specific link in the chain of infection, predicts its effect, and states assumptions. Use it to see the format and depth, then build your own argument for your assigned case.
- Write one defensible claim.
- Choose specific evidence that supports the claim.
- Explain the scientific rule that connects the evidence to the claim.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: Submit your CER in Schoology before the end of the period.
A research team lays out its question, variables, controls, sampling plan, measurement record, and analysis before deciding what the data support.
- Which variable is changed or compared?
- Which conditions and measurements must stay consistent?
- Which conclusion is inside the study's evidence boundary?
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
- • Question and variable cards map to the study design.
- • Control and measurement cards map to fair, reproducible data collection.
- • The conclusion card maps to a bounded claim supported by the analysis.
Part 4 of 4 · Your work▸
Check your work before submitting
- Write a CER with a clear control claim and chain-based evidence.
- State the expected effect and at least one limitation.
4.1 Turn in your work
DueCheck the Schoology assignment for this day- Hand in
- CER naming the highest-priority infection-control intervention, citing chain-of-infection and patient-context evidence, predicting the expected effect, and stating assumptions and limitations.
How to submit and name your file
Submit as one PDF in Schoology.
In Schoology, open your course and the assignment for this lesson. Attach your file, select Submit, and check that it appears in the submission.
PDF upload helpYou get two school days for every day you were absent, so this deadline moves with you.
Today's lesson is in Schoology
Each school day has one lesson page in Schoology that holds everything for the day: the goal, the story so far, every table and data value, the numbered steps, and what to turn in. Open it first and work from it. The other rows for this day, if any, are the score line for a paper quiz or test and the John Carroll debate item; they do not add work. Check Schoology for each deadline.
- Today's Lesson · Wed 11/18 · Wk13 · Riley's karyotype and diagnosis, then the Kim family and how a gel finds a mutation(today's lesson page: the goal, the data, the steps, and what to turn in are all on it)
Link will not open? Open Schoology, choose your course and section, and find the title shown above.
- CompleteEvery required part of the artifact is present, nothing left blank.
- AccurateThe science and the data are correct and match the evidence.
- Scientific reasoningYou explain your claim with evidence and reasoning (CER), not just an answer.
- Professional communicationClear, organized, labeled, and written the way a clinician or scientist would.
- SubmittedGo to Schoology to turn this in. Submit one PDF. Schoology attaches your name to your upload; on the page itself, write your period and code. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf. If you cannot get in, see Mr. Mendoza. Do not skip the work.
How this lesson connects
Keep using what you learned last class: You must locate the single weakest link in a specific case before prescribing a control, because a targeted fix aimed at the real weak point works while a general hygiene tip cannot be tested or aimed. Today: An infection-control CER earns trust because it names the mechanism, predicts an outcome, and states its assumptions, so anyone can test whether the control actually works.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about infection-control CER. It cannot prove causation, diagnose a real patient, or justify action outside this room.
A student writes: 'We should disinfect the shared cuff (claim). The cuff moved between patients (evidence). Disinfecting the cuff is a good idea (reasoning).' What is wrong with the reasoning, and how do you fix it?
Write an answer and pick a confidence to unlock the key.
Fast retrieval with instant answers, not the commit-then-reveal check above. Try each from memory first: write what you remember about the earlier units, then check yourself here.
Missed class or ready for more?▸
Optional practice for this unit's lab skills. Nothing in it is due today.
What today's skills lead to. These are real health-science careers this course builds toward. Tap one to see, on the US Department of Labor's O*NET site, what the job actually involves, what it pays, and how fast it is growing.
Today is individual work you can do from home: complete the same target above, then submit your CER.
Go to Schoology to turn this in. Submit one PDF. Schoology attaches your name to your upload; on the page itself, write your period and code. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf. If you cannot get in, see Mr. Mendoza. Do not skip the work.
Class still runs. Complete today's work as this page describes (it is self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
CDC: infection control basics and the chain of infectionThe optional extra-credit track is open. Complete reserved-unit work from home, including virtual labs, for extra credit. Each item shows its correct submission route.
Open the extra-credit trackSources: slides, readings, and resources▸
The deck carries the prior idea forward, lets you inspect an analogy, maps the rule to biology, and ends with the same evidence decision and exit ticket used on this page.
Hand-picked readings and interactives for this lesson, from authoritative open organizations and PLTW's own public course outline.
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