Task 2.7: Analyze New Data and Suggest Next Steps

You and your colleagues have now been asked to analyze the new line listing in order to determine the next steps in the investigation. You then need to consider your options in terms of where the investigation should go next, and come to a consensus as a team as to which avenues to pursue. The steps below will walk you through this process.

1. Review the email from Dr. Lyons to confirm your understanding of the task.
   
   
2. Download and review the documents attached to Dr. Lyons’ email (Case Control Line Listing, Case Control Questionnaire ) both to see what is there and to get a feel for what resources you have available to you in this task.
   
   
   • Please note: In the Line Listings and elsewhere throughout this rotation the "Date" for each patient is listed as a number (e.g., +1 day) rather than an actual date. In a real outbreak investigation the exact date would be provided rather than a number of days. Due to the mechanics of this rotation, the day Ella Cruz became ill is used as the reference point. The "Date" other patients became ill is the number of days before (-) or after (+) the day Ella Cruz became ill.
     
     
   • Each team member should download a copy of this document and keep his/her own notes. Each of you may notice different things, which will be helpful to share with each other and discuss.
     
     
3. Meet with your team to discuss the task.
   
   
4. Use the Resources link (above) to do additional research as needed throughout the task.
   
   

Analyze Line Listing Data

As in previous tasks, you will use the line listing as both a summary of the cases in the investigation and to help you identify patterns and oddities across the cases.

• Please note: If in your research you encounter information on doing matched analysis for the case-control study, you've been doing very good research. A matched analysis, however, is not always needed and for the purposes of this rotation will not be done.
  
  
1. Review the hypotheses still under consideration that were tested with the case control study. These should be listed in the Case Control Study Template you submitted in the previous task. Thinking just of these hypotheses:

• Keep in mind the purpose of the control study and how data from the controls suggest that the hypotheses are correct or incorrect.
  • Does any of the data you see suggest that the ideas you are pursuing for a source for this infection are correct?
    
    
  • Does any of the data you see refute those ideas?
    
    
2. Determine the odds ratio for each exposure variable.
   • This number will help identify exposures that are associated with disease. (The process to develop the odds ratio should be known to you from the statistics track. There is also information in the Resources link(above) to help you if needed.) Calculate odds ratios using a 2 by 2 table for each of the variables you identified in your hypotheses.
     
     
   • Please note: Odds ratio here does not give an estimate of risk.
     
     
• If none of the hypotheses you tested for show significance, you may need to check your calculations or test other hypotheses.
  
  

Revise Your Hypotheses

As you have been reviewing the data in the line listing, you and your teammates have been discussing how the new information impacts your thinking about the investigation and the source of the outbreak. This means you have been informally revising your hypotheses. It is now time to formally record your current thinking about the hypotheses.

1. Use the Investigation Status and Plan template that you used in earlier tasks, and update it, saving it under a new name.
   
   
2. The source for your supporting and refuting evidence can be the line listings, the case-patient profiles, the estimates of risk and odds ratios, or any information that you had about cocci prior to sending out the questionnaire.
   1. Note all supporting evidence, even if it seems to be balanced by refuting evidence.
      
      
   2. Note where supporting evidence is not necessarily clear or valid (e.g., odds ratio is higher than expected but not high enough to provide clear evidence).
      
      
3. Include in the “Comments and Next Steps” column any thoughts you have about how you would go about resolving any discrepancies between the refuting and supporting evidence, or bolstering your supporting evidence.
   
   

Determine the Next Steps

1. Refer back to the Investigation Process Flow, in the Resources link (above) to remind yourself of any protocol to follow in these circumstances.
   
   
2. Discuss all the different potential actions with your team, and come to consensus about how to proceed. Consider next steps in the three areas listed below.
   1. Data collection and analysis: Now that you have collected this new information and done some analysis of that data, what do you think is the best path in order to identify the source of this outbreak?
      
      
   2. Hypothesis development and testing: Based on your analysis of the line listing, how have your hypotheses changed? How will you go about exploring those hypotheses?
      
      
   3. Management and communication: What data, if any, do you have that you need to share with the medical community? A governing body? The public? The media?
      
      
3. Record the plan in the Investigation Status and Plan Template (ISP) in the appropriate sections.
   
   
4. Provide a summary of your thoughts in an email to Dr. Lyons, including the following elements in your response:
   1. each possible area of action,
      
      
   2. your suggested next steps in relation to that area, and
      
      
   3. your rationale for the actions you have chosen, including where you have decided not to act.
      
      

Review and Submit your Work

1. Review your work.
   • Did you conduct a thorough analysis of the data that was provided, accounting for how the data impacted your earlier hypotheses?
     
     
   • Did you review all possible avenues of exploration at this juncture, develop a plan to move forward and back it up with sound reasoning in your ISP?
     
     
   • Did you summarize your plan in your email response to Dr. Lyons?
     
     
2. Submit your work.
   • Review the checklist located in the Submit Your Work section of this task to ensure completion of the task before submitting your deliverables to your mentor.
     
     

Cross-Team Conference

During outbreak investigations, investigators are charged to continually apprise their colleagues of any progress that has been made. In the spirit of this tradition, you will have periodic 'cross team' conferences where one team presents the state of the world and any recommendations made for next steps.


On these “What next?” tasks, all the teams in the cohort will meet to have a roundtable discussion of what steps were suggested. One team per conference will be responsible for presenting their thoughts on next steps and strategies.

1. Contact your mentor to determine which team will be presenting in this round.
   1. If your team will be presenting, meet with your teammates briefly to determine how to divide up the presentation of a brief history of the outbreak, and strategies and next steps in each of the three areas (data collection and analysis, hypothesis development and testing, and management and communication). Since you are presenting material you have already been discussing for a substantial period of time, the preparation required should be minimal. Remember: This is intended to be an informal discussion.
      
      
   2. If your team will not be presenting, it is still important to review the strategies and next steps you recommended, so as to be ready to give thoughts and feedback to the team who does present.
      
      
2. The presenting team leads the discussion with a brief overview of pertinent facts about the outbreak and the key strategies that they recommended to Dr. Lyons.
   
   
3. The other teams are given an opportunity to respond with thoughts and comments. The discussion is mediated by the mentor.
   
   
4. The mentor summarizes the points made before closing the discussion.
   

Task 2.7 Resources

While Wikipedia is a valuable resource, unlike some other websites anyone can contribute to or modify the site (whether they're knowledgeable about the topic or not). As a result, the site is subject to constant change by questionable sources. Be sure to cross-check information on Wikipedia with other reputable sites to ensure accuracy.

Ask the Expert

What additional steps might be done after a case-control study?

General Resources

Hypotheses and the Scientific Method FAQ
This FAQ supports you in creating and testing scientific hypotheses, with examples and explanations.

Hypotheses for Epidemiology FAQ
General information on hypotheses and testing with emphasis on hypotheses for epidemiology studies.

Medline Plus
A medical dictionary from Medline Plus to help with scientific terms.

Investigation Process Flow
A flowchart that explains the standard procedure that is taken at the CDC during an outbreak investigation.

Line Listing and Analysis

Developing the Line Listing
A description of what a line listing is, how to build a line listing, and a list of variables frequently included in a line listings.

Sample Line Listing 1
An example of a line listing in Table 1 used for a Dengue outbreak is about a third of the way down.

Case-Control and Cohort Study FAQ
Frequently Asked Questions about Case-control and Cohort studies including the steps involved in each study, the advantages and disadvantages to each, how to calculate Odd Ratios and Relative Risk, and how to interpret the results.

Coccidioidomycosis (cocci)

Cocci Overview from CDC
Information from the Centers for Disease Control and Prevention (CDC) on cocci clinical features, transmission, risk groups, challenges, and other important info.

Cocci Overview 1
Includes common symptoms as well as tests and exams to detect the disease.

Cocci Overview 2
Includes x-rays of a cocci patient.

Cocci Overview 3
Includes a map of endemic areas (from Wikipedia).

Cocci Overview 4
Includes incubation periods, clinical signs, and communicability in both humans and animals from The Center for Food Security and Public Health at Iowa State University.