Data analysis 1

Readings

• Thrusfield M (2005) Veterinary Epidemiology. Blackwell Science, London. pp 188 - 204 (questionnaires and data management).
• Thrusfield M (2005) Veterinary Epidemiology. Blackwell Science, London. pp 152 - 156 (data types).
• Thrusfield M (2005) Veterinary Epidemiology. Blackwell Science, London. pp 214 - 216 and pp 220 - 224 (descriptive statistics, including confidence intervals).
• Thrusfield M (2005) Veterinary Epidemiology. Blackwell Science, London. pp 217 - 220 (statistical distributions).
• Thrusfield M (2005) Veterinary Epidemiology. Blackwell Science, London. pp 224 - 227 (presenting numerical data).
• Dohoo I, Martin S, Stryhn H (2003) Veterinary Epidemiologic Research. AVC Inc, Charlottetown, Prince Edward Island, Canada. pp 53 - 63 (questionnaires), pp 581 - 586 (data management), pp 586 - 589 (data analysis).
• Petrie A, Watson P (2005) Statistics for Veterinary and Animal Science. Blackwell Science, London. pp 153 - 156 (transformation).

Presentations

• Design and conduct of questionnaires. What different types are there, and what are the strengths and weaknesses of each?
• Methods of data management. Common data problems, what effect they can have on the interpretation of the data, and how to avoid them.
• Summarise the different types of data. For each type provide a definition and example.
• Displaying data: measures of centrality and dispersions, confidence intervals.
• Data distributions and transformations. When is transformation indicated, and how do you do it?

Exercises

Compare and contrast methodologies used for the following questionnaires, concentrating on the principles of design and conduct:

• Baldock FC, Alexander L, More S (2003) Estimated and predicted changes in the cat population of Australian households from 1979 to 2005. Australian Veterinary Journal 81: 289 - 292.
• Buckley P, Dunn T, More S (1995) Owners' perceptions of the health and performance of Pony Club horses in Australia. Preventive Veterinary Medicine 63: 121 - 133.
• Heller J, Bosward KL, Hodgson JL, Cole FI, Reid SWJ, Hodgson DR, Mellor DJ (2005) Snake envenomation in dogs in New South Wales. Australian Veterinary Journal 83: 286 - 292.
• Wraight MD, McNeil J, Beggs DS, Greenall RK, Humphris TB, Irwin RJ, Jagoe SP, Jemmeson A, Morgan WF, Brightling P, Anderson GA, Mansell PD (2000) Compliance of Victorian diary farmers with current calf rearing recommendations for control of Johne's disease. Veterinary Microbiology 77: 429 - 442.

Example examination questions

1. Using examples, write brief notes on data types (2000 written).

2. Write brief notes to demonstrate your understanding of when it is appropriate to use postal questionnaires to conduct epidemiological surveys and how to address the potential weaknesses of this method (1998 written).

3. Write brief notes using examples about paired versus independent data (1997 written).

Additional reading

• Epidemiological Skills in Animal Health, PGFVS Proceedings 143; pp 151 – 158 (questionnaires), pp 215 - 222 (data types and descriptive statistics).
• Cameron A. (2004) Data management for animal health. AusVet Animal Health Services, Brisbane, Australia.
• Salman MD, Curtis CR, Shott S (1990) Data description. Journal of American Veterinary Medical Association 197: 36 - 38
• Shott S (1990) Confidence intervals. Journal of American Veterinary Medical Association 197: 576 - 578.