Description: Analysis of Research Scenarios
Assessment Item 3
Description: Analysis of Research Scenarios
Value: 50%
Due Date: Friday May 28
Length: 2000 words
Preparation: This assessment covers all topics, with a focus on Topics 8-11.
Task: Provide short answers to the questions about the 5 research scenarios provided.
A separate document containing the assessment questions will be located in the Learnline unit under Assessment Tasks/Assessment 3.
Presentation:
Short answers:
Write your answers in this template directly under the respective questions. Please attempt to complete all questions. Any question unaddressed is a missed opportunity.
Make sure you check the grammar, spelling and clarity of your answers.
Please provide references in Vancouver style for questions where you are asked to comment, define, describe or explain your answer. Marks will be deducted for insufficient referencing.
Please stick to the word limit. References are not included in the word limit. Marks will be deducted for going over the word limit.
Calculations:
Where you are asked to perform a calculation, please show every step you have taken. Do not round up until you have completed your calculations. Final answers should be rounded up to one decimal point.
Document type:
Please submit your assignment as a Word document, not a PDF. Please do not submit handwritten or partially handwritten assignments.
Assessment criteria: Accuracy of responses to the scenarios. Marks allocated per question.
See the assessment question document in Learnline for details.
SCENARIO 1 (20 marks)
Read the following publication and answer the questions below:
Henshall C, Davey Z, Srikesavan C, Hart L, Butcher D, Cipriani A. Implementation of a Web-Based Resilience Enhancement Training for Nurses: Pilot Randomized Controlled Trial. J Med Internet Res. 2023 Feb 14;25:e43771. doi: 10.2196/43771. PMID: 36787181.
What was the study aim/objective (max 100 words) 2 marks
How were cases and controls identified (max 100 words) 2 marks
Identify potential biases and confounders (max 200 words) 4 marks
How was bias and confounding addressed (if at all, max 100 words) 2 marks
Discuss the appropriateness and display of data (max 100 words) 2 marks
Briefly discuss the statistical tests used (max 50 words) 1 marks
What was the study conclusion? (max 100 words) 2 marks
Are the conclusions generalizable to other settings? Justify your answer (max 200 words) 5 marks
SCENARIO 2 (20 marks)
The Minister for Health has asked you for some up-to-date information about the link between teenage use of cannabis and psychosis. In your search, you find a case-control study which compared patients presenting with first-episode psychosis to controls from the same location. In the study the researchers examined the age at first use, frequency of use and type of cannabis to assess the risk of psychosis. Details of the findings are shown in the below table. BTW: these numbers are not from an actual study.
Table: Number of cases and controls per risk factor (exposure)
Psychosis
Cannabis Overall Yes No
Yes 203 118
No 135 138
Frequency <1x / week 40 66
<3x / week 65 35
Daily 98 17
Type No use 135 138
Hash 108 59
Grass 95 59
Age of 1st use <15 years? Yes 152 45
No 51 73
Considering the above table:
To quantify the relationship between exposure and outcome you need to calculate the odds ratio (OR) or the relative risk (RR), which one do you choose? Please justify your choice (max 50 words) 2 marks
Calculate the OR or the RR for the association between cannabis use and psychosis. How much higher are the odds of exposure / relative risk among the cases compared to the controls? Express your answer as a percentage 2 marks
Calculate the OR or RR for the association between frequency of cannabis use and psychosis, using non-users as the reference category. Do you see a dose effect? (max 75 words) 5 marks
Calculate the OR or RR for the association between type of cannabis use and psychosis, using non-users as the reference category (max 50 words) 2 marks
Calculate the OR or RR for the association between young age (<15 years) at first use of cannabis use and psychosis, using non-users as the reference category. Discuss the relationship between age at first use of cannabis and psychosis (max 50 words) 4 marks
In your own words explain what the term Populations attributable fraction means (50 words) 2 marks
In your own words explain what a p-value describes (50 words) 2 marks
What are the most common levels of significance used? 1 mark
SCENARIO 3 (15 marks)
A study undertaken to determine the diagnostic utility of a rapid diagnostic test for Covid-19 tested 640 individuals who presented with suspected C19 infection. The rapid diagnostic test (RAT) results obtained from participants were compared with results obtained by the gold standard test clinical PCR. Of the 640 individuals, 578 were rapid diagnostic test positive and PCR positive (100% sensitivity) while 16 were rapid diagnostic test positive and PCR negative.
Using the information provided so far, complete the 2X2 table below 3 marks
Calculate the sensitivity and specificity of the rapid diagnostic test 2 marks
Calculate the positive and negative predictive value of the rapid diagnostic test 2 marks
Would you recommend the use of this test for population screening? Why? (max 75 words) 5 marks
Point-of-care rapid diagnostic test PCR
Positive Negative Total
Positive Negative Total Describe the relationship between predictive values and prevalence (max 50 words) 3 marks
SCENARIO 4 (20 marks)
An outbreak of foodborne illness occurred among attendees of a restaurant on the 1st of April 2023. Data below were collected from all attendees (n=65).
Table SEQ Table * ARABIC 1 Attack rate per risk factor (exposure)
Menu item Attack rate
Total Exposed Exposed Not exposed
Oysters 33 72% 41%
Mixed salad 17 61% 55%
Pasta 38 43% 67%
Potato salad 6 33% 62%
Lasagne9 47% 64%
Chicken 11 83% 6%
Cheesecake 45 42% 65%
Cheese & biscuits 20 63% 54%
Calculate the number of attendees who became ill and the number who did not become ill (show your workings). Document your results in the table on the next page 6 marks
Menu item Ate Did not eat Total Ill Not ill Sub-total Ill Not ill Sub-total Measure of association
Oysters 65 Mixed salad 65 Pasta 65 Potato salad 65 Lasagne65 Chicken 65 Cheesecake 65 Cheese & biscuits 65 Would you apply a relative risk or an odds ratio to analyze the relationship between exposure and outcome in this study and explain your choice? (max 50 words) 2 marks
Calculate the relevant statistic (measure of association) for each risk factor (show your workings). Document your results in the table below 4 marks
Which food item was the apparent source of food poisoning? Explain why you think this particular food item was the source? (max 50 words) 2 marks
Find an example of another outbreak caused by the same food item and discuss the type of microorganism and its mode of transmission. Reference your answer (max 150 words) 6 marks
SCENARIO 5 (15 marks)
An outbreak of acute gastroenteritis occurred among passengers on board a ship travelling on a cruise between 3 January to 17 January inclusive. Investigators conducting a retrospective analysis of the outbreak sent questionnaires to all passengers. Of the 1,842 passengers, n=236 passengers met the case definition for norovirus infection. The following line listing shows the number of cases who met the case definition during the 15-day period.
Table: Line listing
Date No. of cases Date No. of cases
3-Jan 6 11-Jan 18
4-Jan 21 12-Jan 14
5-Jan 36 13-Jan 6
6-Jan 29 14-Jan 1
7-Jan 32 15-Jan 0
8-Jan 16 16-Jan 0
9-Jan 24 17-Jan 0
10-Jan 33 18-Jan 0
What are the symptoms of norovirus infection? (max 50 words) 2 marks
Develop a case definition to describe for the 236 (remember, time, place, simplicity; max 75 words) 5 marks
Using the data from the line listing, construct an epi curve showing the number of cases per day. Hint: use excel to construct your epi curve and paste a screen shot of the figure in your answer 3 marks
What sort of transmission does the epi curve illustrate (max 50 words)? 2 marks
A 2nd peak occurred on day 8 what do you think may have caused this 2nd peak? (max 75 words) 3 marks
Total = /90 (As this assessment is worth 50%, marks will be converted to a score out of 50)
