| Course | NU743 Clinical Decision-Making and Collaboration |
|---|---|
| Unit | Unit 5 |
| Paper type | Decision tree |
| Length | About 870 words, 6 pages double-spaced |
| Format | APA 7 student paper |
| School | Purdue University Global |
| Program | Doctor of Nursing Practice (DNP) |
| Updated | September 2026 |
Free sample paper for NU743 Unit 5
Surgery Now or Antibiotics First: A Decision Tree of Expected Days Away From Work for a 34-Year-Old Self-Employed Roofer With Uncomplicated Appendicitis and No Appendicolith, With Two Sensitivity Analyses
[Student Name]
Purdue University Global
NU743: Clinical Decision-Making and Collaboration
Unit 5 Decision Tree
[Instructor Name]
[Date]
The patient is composite; probabilities and days away from work are bracketed estimates drawn from the cited trials and stated assumptions.
The Decision and the Outcome
Mr. [T.], [34], runs a small roofing business and is paid only when he works. CT confirmed uncomplicated appendicitis without an appendicolith. He asked which option would keep him off roofs for the fewest days. That question defined the tree's outcome: expected days away from work over the following year. Other outcomes matter, such as complications and the chance of later surgery, and they are discussed below, but the tree answers his question.
The Tree
The tree runs from a single decision node with two arms.
Surgery arm. One chance node: a complication after planned laparoscopic appendectomy, probability [0.05], leading to [20] days away from work; no complication, probability [0.95], leading to [8] days.
Antibiotics arm. The first chance node is failure within [90] days, requiring appendectomy, probability [0.25]; this branch costs [4] days for the antibiotic episode plus [8.8] for surgery and recovery, [12.8] in total. The second chance node follows early success, probability [0.75]: recurrence later in the year requiring surgery, probability [0.15], again [12.8] days; or no recurrence, probability [0.85], [4] days.
Inputs and Their Sources
The [0.25] failure probability comes from the CODA trial, in which [25] percent of patients without an appendicolith treated with antibiotics had undergone appendectomy by [90] days (CODA Collaborative, 2020). The recurrence probability of [0.15] later in the first year is an assumption informed by longer follow-up: in the APPAC trial, recurrent appendicitis continued to occur after the first year, with a cumulative incidence of about four in ten by five years (Salminen et al., 2018). The complication probability of [0.05] after planned surgery is an estimate for uncomplicated laparoscopic appendectomy. Days away from work are estimates for a manual worker and are the least certain inputs; the plausible range for surgery recovery is [6 to 14] days.
Rolling Back the Tree
Decision analysis compares options by computing the expected value at each chance node, working back from the outcomes to the decision (Detsky et al., 1997). The calculation can be checked by hand.
For surgery: [0.95] times [8] is [7.6], plus [0.05] times [20] is [1.0], giving [8.6] days.
For antibiotics, first the success branch: [0.85] times [4] is [3.4], plus [0.15] times [12.8] is [1.92], giving [5.32]. Then the arm: [0.25] times [12.8] is [3.2], plus [0.75] times [5.32] is [3.99], giving about [7.2] days.
Antibiotics save about [1.4] expected days. That difference is an average across many hypothetical patients like him; any one patient will experience one branch, either about four days or nearly thirteen, and never the average itself. Explaining that distinction to Mr. [T.] mattered as much as the number.
On the outcome he cares about, antibiotics come out ahead, but only by a day and a half, and only while the chance of failure stays well below one in two.
Sensitivity Analysis 1: Failure Probability
Holding everything else fixed, the expected days for antibiotics equal those for surgery when the failure probability reaches about [0.44]. Below that, antibiotics win on days lost. For patients with an appendicolith, CODA found a failure rate of [41] percent by [90] days and a higher rate of complications with antibiotics (CODA Collaborative, 2020); at [0.41] the antibiotic arm yields about [8.4] days, close to surgery, and the complication difference would tip the choice toward surgery. Mr. [T.] has no appendicolith, so his estimate sits well below the threshold.
Sensitivity Analysis 2: Recurrence Later in the Year
Holding failure at [0.25], antibiotics equal surgery when the probability of recurrence later in the year reaches about [0.36]. The base estimate of [0.15] is well below that, but because recurrence continues beyond one year, a tree that ran for five years would narrow the gap.
What the Tree Leaves Out
The tree counts days, not other things Mr. [T.] may care about. Antibiotics carry a real chance of surgery later, at an unplanned time, perhaps during a busy season. CODA found that complications were more frequent with antibiotics overall, a difference attributable to patients with an appendicolith rather than those without. And some patients value certainty over a small gain in days. I presented the tree's result as a starting point for his decision, not as the decision itself.
The Script
A short appendix script, about [30] lines, stores each probability and outcome, rolls back both arms, and loops over the failure and recurrence probabilities to find the thresholds. Its output matches the hand calculation above, and a reader can change any input to test a different patient.
The Choice He Made
After seeing the tree and the thresholds, Mr. [T.] chose antibiotics, saying that a day and a half mattered to him and that he understood the chance of surgery later. He asked to be told what symptoms should bring him back.
References
CODA Collaborative. (2020). A randomized trial comparing antibiotics with appendectomy for appendicitis. New England Journal of Medicine, 383(20), 1907-1919. https://doi.org/10.1056/NEJMoa2014320
Detsky, A. S., Naglie, G., Krahn, M. D., Naimark, D., & Redelmeier, D. A. (1997). Primer on medical decision analysis: Part 1. Getting started. Medical Decision Making, 17(2), 123-125. https://doi.org/10.1177/0272989X9701700201
Salminen, P., Tuominen, R., Paajanen, H., Rautio, T., Nordström, P., Aarnio, M., Rantanen, T., Hurme, S., Mecklin, J.-P., Sand, J., Virtanen, J., Jartti, A., & Grönroos, J. M. (2018). Five-year follow-up of antibiotic therapy for uncomplicated acute appendicitis in the APPAC randomized clinical trial. JAMA, 320(12), 1259-1265. https://doi.org/10.1001/jama.2018.13201
What the NU743 Unit 5 assignment asks for
The Unit 5 assignment asks you to structure a clinical decision as a decision tree and compute which option is expected to be better. Plan to define the decision and the outcome, draw decision and chance nodes, source each probability and outcome value, roll the tree back, run at least one sensitivity analysis and discuss what the model omits. Around 900 words with a diagram, an input table and sometimes a short script is common. Faculty reward trees with an outcome that matters to the patient, inputs traced to trials or clearly labeled as assumptions, a rollback that can be checked by hand, and sensitivity analyses that report thresholds. State plainly that the expected value is an average, since any one patient will experience a single branch.
Inside the NU743 Unit 5 example
The paper opens with the decision and why days away from work was chosen as the outcome. The tree is described arm by arm, with probabilities and days on each branch. An inputs section traces the failure rate to CODA, the recurrence estimate to APPAC's longer follow-up and the remaining values to stated assumptions. The rollback is written out step by step and followed by a note that the average is not what any one patient experiences; the highlighted sentence summarizes the margin. Two sensitivity analyses find the failure and recurrence probabilities at which the choice flips, with the appendicolith case as an example. A section lists what the tree leaves out, a short section describes the script, and the patient's choice closes.
Where the points sit in the NU743 Unit 5 rubric
Decision tree exercises are typically marked on structure, inputs, calculation, sensitivity analysis and interpretation. Structure earns credit when decision and chance nodes are drawn correctly and every branch ends in an outcome value. Inputs are judged on whether probabilities and values are sourced or clearly labeled as assumptions, with plausible ranges. Calculation rewards a rollback that can be reproduced. Sensitivity analysis is credited when it reports thresholds rather than only new totals. Interpretation scores well when the paper explains what the result means for the patient and what the model omits, such as complications or the patient's tolerance for uncertainty. Diagrams should be legible and inputs listed in one place.
NU743 Unit 5 help from the desk
One recurring weakness is choosing an outcome the patient did not ask about, such as quality-adjusted life years when he wanted days off work. Another is using probabilities with no source. Some trees omit branches, such as recurrence after early success, which biases the result. Others report expected values without showing the rollback. Many sensitivity analyses change a value without reporting where the decision flips. And some papers present the result as the decision itself. Choose an outcome that matters to the patient, source every input, show the arithmetic, report thresholds, and describe what the tree cannot capture before offering the result as a starting point.
Get an NU743 Unit 5 example written to your instructions
Share the clinical choice your prompt sets, the outcome measure if one is specified, and the rubric. A first custom sample is free and returns within 24-48h with the tree drawn, every input sourced and bracketed, the rollback shown by hand and by a short script, and the threshold where the recommendation would reverse. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
More NU743 papers and DNP samples
- NU743 Unit 1: Reasoning Narrative, Treat in Place
- NU743 Unit 2: Differential Workup, High ALP
- NU743 Unit 3: Discussion Post, PECARN and Observation
- NU743 Unit 4: Case Analysis, Postpartum Headache
- NU743 Unit 6: Bias Self-audit
- NU743 Unit 7: Interprofessional Conflict Analysis
- NU743 Unit 8: Colleague Communication Piece
- NU743 Unit 9: Seminar Reflection
- NU743 Unit 10: Integrated Case Report
- NU733 Unit 5: Statute Analysis, Public Camping Act
- NU713 Unit 5: Seminar Reflection, Reference Groups
- NU703 Unit 5: Literature Synthesis, DNP Role Use
NU743 Unit 5 questions, answered
Does a decision tree need utilities, or are probabilities enough?
Probabilities alone describe what might happen; the tree needs a value at each end to say which path is better. That value can be a utility score, a cost, or a natural unit such as days lost, as it is here. What matters is defining it once, applying it consistently, and saying what it leaves out.
What software should draw and compute the tree?
Whatever your section allows. Spreadsheets, dedicated decision software and short scripts all work, and some faculty accept a hand-drawn diagram with the rollback written out. The sample shows the calculation by hand beside a brief script so a reader can verify it either way. Your prompt may also say whether the working itself is submitted.
Where do the probabilities come from in a composite case?
From published trials and reviews, cited, with a range around each estimate. The sample brackets every figure so it reads as illustrative rather than as a rate for a real patient. Your own tree should draw on sources your faculty accept and show why each estimate fits the patient in your prompt.
Where can I find a free NU743 Unit 5 sample paper?
The complete NU743 Unit 5 decision tree appears here: the choice and its outcome measure, both arms, sourced inputs, a hand rollback, two sensitivity analyses, what the tree leaves out, the script and the patient's choice, plus three references. A tree for your own clinical decision can be drafted.
At what failure rate would surgery win in NU743 Unit 5?
Holding other inputs fixed, expected days for antibiotics equal those for surgery when the probability of antibiotic failure reaches about 0.44. His estimate without an appendicolith is 0.25, well below that threshold.