- A
Readmission Rate = DIVIDE( COUNTROWS(Readmissions), COUNTROWS(Admissions) )
Why wrong: Counts all readmissions, not first per patient per admission.
- B
Readmission Rate = DIVIDE( COUNTROWS(Admissions), DISTINCTCOUNT(Admissions[PatientID]) )
Why wrong: Divides admissions by patients, not readmission rate.
- C
Readmission Rate = VAR ReadmitPatients = CALCULATETABLE( VALUES(Readmissions[PatientID]), Readmissions[ReadmitDate] <= Admissions[DischargeDate] + 30 ) RETURN DIVIDE( COUNTROWS(ReadmitPatients), DISTINCTCOUNT(Admissions[AdmissionID]) )
Correctly counts distinct patients readmitted within 30 days per admission.
- D
Readmission Rate = DIVIDE( COUNT(Readmissions[ReadmissionID]), COUNT(Admissions[AdmissionID]) )
Why wrong: Counts all readmission events, not first readmission.
Quick Answer
The correct DAX measure is the one using CALCULATETABLE with VALUES and a filter on ReadmitDate within 30 days of DischargeDate, then dividing by DISTINCTCOUNT of AdmissionID. This works because CALCULATETABLE creates a virtual table of unique PatientIDs who had a readmission within the 30-day window, effectively isolating only the first readmission per patient per admission—avoiding double-counting when a patient has multiple readmissions. On the PL-300 exam, this tests your ability to handle row context, filter context, and the common trap of using COUNTROWS on the raw Readmissions table, which would count every readmission instead of distinct patients. A key memory tip: think “first readmission = distinct patient per admission window,” so always use VALUES or DISTINCT to deduplicate before counting.
PL-300 Model the data Practice Question
This PL-300 practice question tests your understanding of model the data. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are a Power BI developer for a healthcare organization. You are building a semantic model to analyze patient readmission rates. The data warehouse contains: Admissions (AdmissionID, PatientID, AdmitDate, DischargeDate, DiagnosisCode, HospitalID) and Readmissions (ReadmissionID, PatientID, ReadmitDate, Reason). You need to create a measure that calculates the readmission rate within 30 days of discharge. The measure must consider only the first readmission per patient per admission. You also need to create a visual that shows the trend of readmission rates over time, allowing users to filter by diagnosis. The model will be used by 200 analysts and must refresh daily. Which DAX measure should you create?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"first"Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Readmission Rate = VAR ReadmitPatients = CALCULATETABLE( VALUES(Readmissions[PatientID]), Readmissions[ReadmitDate] <= Admissions[DischargeDate] + 30 ) RETURN DIVIDE( COUNTROWS(ReadmitPatients), DISTINCTCOUNT(Admissions[AdmissionID]) )
Option C is correct: It calculates distinct count of patients readmitted within 30 days divided by distinct count of admissions, considering first readmission. Option A is wrong because COUNTROWS counts multiple readmissions per patient. Option B is wrong because it counts all admissions including those without readmission. Option D is wrong because it counts all readmissions, not first.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Readmission Rate = DIVIDE( COUNTROWS(Readmissions), COUNTROWS(Admissions) )
Why it's wrong here
Counts all readmissions, not first per patient per admission.
- ✗
Readmission Rate = DIVIDE( COUNTROWS(Admissions), DISTINCTCOUNT(Admissions[PatientID]) )
Why it's wrong here
Divides admissions by patients, not readmission rate.
- ✓
Readmission Rate = VAR ReadmitPatients = CALCULATETABLE( VALUES(Readmissions[PatientID]), Readmissions[ReadmitDate] <= Admissions[DischargeDate] + 30 ) RETURN DIVIDE( COUNTROWS(ReadmitPatients), DISTINCTCOUNT(Admissions[AdmissionID]) )
Why this is correct
Correctly counts distinct patients readmitted within 30 days per admission.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
- ✗
Readmission Rate = DIVIDE( COUNT(Readmissions[ReadmissionID]), COUNT(Admissions[AdmissionID]) )
Why it's wrong here
Counts all readmission events, not first readmission.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related PL-300 NAT questions on configuration and troubleshooting.
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Model the data — study guide chapter
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Model the data practice questions
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FAQ
Questions learners often ask
What does this PL-300 question test?
Model the data — This question tests Model the data — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Readmission Rate = VAR ReadmitPatients = CALCULATETABLE( VALUES(Readmissions[PatientID]), Readmissions[ReadmitDate] <= Admissions[DischargeDate] + 30 ) RETURN DIVIDE( COUNTROWS(ReadmitPatients), DISTINCTCOUNT(Admissions[AdmissionID]) ) — Option C is correct: It calculates distinct count of patients readmitted within 30 days divided by distinct count of admissions, considering first readmission. Option A is wrong because COUNTROWS counts multiple readmissions per patient. Option B is wrong because it counts all admissions including those without readmission. Option D is wrong because it counts all readmissions, not first.
What should I do if I get this PL-300 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related PL-300 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 21, 2026
This PL-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PL-300 exam.
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