Design justification 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 justifying their app design choices against user needs and usability principles.
Check you have the right sheet: the top of it prints today's portal day, Design justification 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: A design is defensible only when each feature traces to user evidence, so a CER forces justification because it makes you link every choice to a real need and a usability principle.
- • Design justification means tracing each feature back to a specific persona need and a usability principle.
- • A prediction about improved communication is based on mechanism, not hope: link the feature to the behavior change it enables.
- • Design assumptions include: that the persona is realistic, that users have smartphones, and that the surge scenario is accurate.
A design serves people only when it is built around a real persona's needs, so a wireframe that ignores the persona is design fiction because nothing on it is ranked by real urgency.
A design is defensible only when each feature traces to user evidence, so a CER forces justification because it makes you link every choice to a real need and a usability principle.
Driving question: Your team put a big 'Nearest Open Clinic' button on screen one. Prove it: which specific persona need and which usability principle make that the right call, rather than just what looked good?
What you already know: A design serves people only when it is built around a real persona's needs, so a wireframe that ignores the persona is design fiction because nothing on it is ranked by real urgency.
New idea: A design is defensible only when each feature traces to user evidence, so a CER forces justification because it makes you link every choice to a real need and a usability principle.
Visual or model: No figure is attached to this lesson. The readings, the worked example and E1 to E3 carry the evidence.
- Observe or measure the relevant feature in design justification CER.
- Organize the observation with a stable evidence ID.
- Apply this rule: A design improves when evidence is compared with explicit criteria and constraints.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: Today the biomedical team uses Design justification CER to make a bounded evidence decision. A classroom , , presentation, or does not establish clinical , effectiveness, manufacturing quality, or regulatory clearance.
What the evidence supports: E1 to E3 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.
- • : A health system's ability to rapidly expand staff, beds, and supplies to handle a sudden jump in patients during an emergency or outbreak.
- • : Healthcare delivered to people where they are, using vehicles or portable units to reach communities far from a fixed clinic or hospital.
- • : The science of protecting and improving the health of whole communities through prevention, education, and policies rather than treating one patient at a time.
- • surveillance: The ongoing, systematic collection and analysis of health data to detect disease early, track its trends, and trigger a timely response.
- • communication: Sharing information clearly and accurately between people, which in healthcare keeps patients safe and helps teams coordinate care.
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.
A biomedical design advances when test evidence is compared with explicit user needs, criteria, constraints, risks, and failure modes, then used to justify a documented revision.
Limit: A classroom , , presentation, or does not establish clinical , effectiveness, manufacturing quality, or regulatory clearance.
A design improves when evidence is compared with explicit criteria and constraints.
Limit: Biomedical designs also require , ethics, and biological validation beyond a physical test.
Write a CER justifying design choices with user-need 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 design justification CER supports before submitting the claim-evidence-reasoning response named on today's page.
- • Trace the clinic button to a rushed parent's need for speed and the efficiency principle, which makes the choice defensible.
- • Explain that the button is big, clean, and intuitive, since describing what the feature does is what justifying means.
- • Test the screen with a rushed parent before calling the button justified, because no test evidence yet supports that need.
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 design justification 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 design justification CER supports before submitting the claim-evidence-reasoning response named on today's page.
Context: Today the biomedical team uses Design justification CER to make a bounded evidence decision. A classroom , , presentation, or does not establish clinical , effectiveness, manufacturing quality, or regulatory clearance.
- • T1: State a claim that the design meets the target users' surge needs.
- • T2: Cite persona and feature-list evidence tied to specific needs.
- • T3: Explain reasoning that links each design choice to a usability principle.
- • T4: Predict how the design improves communication during a surge.
- • T5: Identify assumptions and limitations in the design process.
- • E1: A biomedical design advances when test evidence is compared with explicit user needs, criteria, constraints, risks, and failure modes, then used to justify a documented revision.
- • E2: A design improves when evidence is compared with explicit criteria and constraints.
- • E3: Write a CER justifying design choices with user-need evidence.
Measurements: No patient measurement is supplied unless it appears explicitly in E1-E3. Do not invent a value.
Uncertainty: This is a composite classroom scenario. Missing history, measurements, or confirmation tests remain unknown and limit the conclusion.
- • The solution must address the stated need in design justification CER.
- • The decision must be supported by E1-E3.
- • The final product must make the success criteria visible.
- • Complete the work inside the 80-minute block.
- • Use only supplied or teacher-approved materials and evidence.
- • Do not trade , accessibility, or privacy for speed.
- • and evidence quality: must pass before scoring other criteria.
- • User need and effectiveness: highest scored criterion.
- • Time, cost, and ease of use: compare only after and effectiveness pass.
Test evidence: For each option, record the E1-E3 result that supports or fails each criterion. Do not assign a score without a named observation.
- Which version or option did you test?
- Which requirement did it meet or miss?
- Which evidence shows that, and what did it say?
- What did you change?
- Why did you change it?
- Who is this for, and what do they need?
- What must it do, and what limits you?
- Which option did you choose, and what evidence backs it?
- What did you test, and what happened?
- What did you change, and why?
Students often think explaining a design means describing what the feature does or saying it looks good and feels intuitive. The trap: because describing a feature is not justifying it. A real justification traces the choice to a specific persona need and a named usability principle, so 'it looks clean' is opinion while 'it serves a rushed parent's need for speed, meeting the efficiency principle' is evidence.
- 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 Design justification 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 that the design meets the target users' surge needs.
Show all 5 required steps
- State a claim that the design meets the target users' surge needs.
- Cite persona and feature-list evidence tied to specific needs.
- Explain reasoning that links each design choice to a usability principle.
- Predict how the design improves communication during a surge.
- Identify assumptions and limitations in the design process.
Lost your place? Need your place? The CER moves in five steps: state the claim, cite persona and feature-list evidence, explain reasoning that links each choice to a usability principle, predict the communication improvement, then name assumptions and limitations. Continue at the step you left.
- 0-8 minReview the personas and wireframe you built last class; identify two design choices you can most strongly justify.
- 8-20 minWrite the claim: one sentence stating the design meets target users' surge communication needs.
- 20-42 minWrite evidence: cite persona needs and specific feature-list items as separate evidence points.
- 42-58 minWrite reasoning: link each design choice to a named usability principle.
- 58-70 minWrite prediction and add design assumptions and limitations.
- 70-80 min: confirm claim is specific, evidence cites persona, limitation is stated.
- • Your team designed an app yesterday; today you write the individual argument for why each choice was the right one.
- • The CER claim must be specific: not 'the design is good' but 'the design meets the communication needs of elderly users during a surge.'
- • Cite the persona and feature list, not just your memory of the discussion.
- • Your prediction tells the reader what will happen differently because of your design, compared to no app at all.
PLTW connection and today's work
In myPLTW, go back to Problem 3.3.2 Public Health Emergency Apps in Lesson 3.3 Information Sharing and use it as the scaffold for your CER.
Today's stopping point: The myPLTW prompts done in the first 10 minutes; full CER submitted 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
- Problem 3.3.2 Public Health Emergency Apps
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: Our lobby wayfinding kiosk design meets the navigation needs of our two target users at a large hospital, an older first-time visitor named Ellen and a hurried delivery driver named Marcus.
Evidence (persona and feature list): Ellen needs to reach a department she has never visited and reads slowly, so we made the home screen a single large question, "Where are you going?", with a short list of the most-visited departments in big high-contrast text. Marcus needs the loading dock and its entrance quickly and only glances at the screen, so we added a persistent "Deliveries and Dock" button in the same fixed spot on every screen and a printable step-by-step route card.
Reasoning (tie each choice to a usability principle): The single-question home screen serves simplicity, because it removes competing choices and shows one clear task at a time. The big high-contrast text serves accessibility, so a user with weaker vision like Ellen can still read it without help. The fixed-position "Deliveries and Dock" button serves consistency, because Marcus can find the same control in the same place every time and does not have to relearn the screen. The printable route card serves memory support, so a user does not have to hold every turn in their head while walking a long hallway.
Prediction: Because the design cuts the reading load and the number of choices that usually make people freeze or ask staff for help, more visitors should reach the right department on their own and fewer should crowd the information desk, which is the behavior change we want in a busy lobby.
Assumptions and limitations: We assume our two personas represent most kiosk users, that visitors can stand and touch a screen, and that department names on the kiosk match the signs in the hallways. If many users are in wheelchairs and cannot reach a tall screen, or if the building signs use different names than the kiosk, then the design would fail those users and our claim would need to change. A lower screen height and matching signage would matter more than any button we added.
This model shows the level of evidence and organization needed to complete: Parallel worked model of a design-justification CER: for a different product (a hospital lobby wayfinding kiosk), it traces each design choice to a persona need and a usability principle, predicts the effect on behavior, and states assumptions and limitations, so students see the format and depth without seeing an answer to their own clinic-app prompt.
- 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 end of period.
A bridge is tested against a load limit, cost limit, and user need before revision.
- Which requirement is a criterion?
- Which limit is a constraint?
- What test result should trigger a redesign?
A design improves when evidence is compared with explicit criteria and constraints.
Biomedical designs also require , ethics, and biological validation beyond a physical test.
- • Bridge requirements map to what the device must do for the body.
- • Load results map to the measurements taken from the .
- • Revision maps to the change those measurements justify.
Part 4 of 4 · Your work▸
Check your work before submitting
- Write a CER justifying design choices with user-need evidence.
- Tie choices to usability principles and state one limitation.
4.1 Turn in your work
DueCheck the Schoology assignment for this day- Hand in
- CER with a specific design-claim, persona and feature-list evidence, reasoning linking choices to usability principles, a communication improvement prediction, and design 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.
- Outbreak unit test: the hospital investigation (paper, in class Wed 12/9)(taken on paper in class: this row holds the score, there is nothing to upload)
- Today's Lesson · Wed 12/9 · Wk16 · Outbreak unit test on paper, then record and share your podcast(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: A design serves people only when it is built around a real persona's needs, so a wireframe that ignores the persona is design fiction because nothing on it is ranked by real urgency. Today: A design is defensible only when each feature traces to user evidence, so a CER forces justification because it makes you link every choice to a real need and a usability principle.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about design justification CER. It cannot prove causation, diagnose a real patient, or justify action outside this room.
A team writes: 'We added a big open-clinic button because it looks clean and modern.' Rewrite this as a real design justification.
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?▸
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:
Ready.gov: pandemic and large-scale health emergenciesThe 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.
This week
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