Data Analysis & Interpretation Intermediate Injury Prevention August 23-26, 2011 Billings, MT

Data Analysis & Interpretation Session Objectives: Review basic epidemiologic concepts & terms. Describe and apply basic statistics to injury prevention.

Data Analysis & Interpretation Epidemiologic Concepts & Terms Epidemiology Population-based Injuries are not random Risk Morbidity v. Mortality

Data Analysis & Interpretation Epidemiologic Concepts & Terms Epidemiology: “The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to control health problems” Who Where When What Why How - A Dictionary of Epidemiology

Data Analysis & Interpretation Epidemiologic Concepts & Terms Epidemiology is POPULATION-BASED (concerned with the community, not the individual). Leading Causes of Unintentional Injury Death, Florida, MVC 2.Poisoning 3.Fall 4.Drowning 5.Suffocation

Data Analysis & Interpretation Epidemiologic Concepts & Terms Injury is not randomly distributed in a population. MP272.5

Data Analysis & Interpretation Epidemiologic Concepts & Terms MortalityMorbidity Fatalities Data easier to obtain Tip of the pyramid Non-fatal Difficult to obtain More complete description of the magnitude of the problem

Data Analysis & Interpretation Epidemiologic Concepts & Terms Risk: - A Dictionary of Epidemiology “The probability that an event will occur.”

Data Analysis & Interpretation Epidemiologic Concepts & Terms - A Dictionary of Epidemiology Risk Factor: “An attribute or exposure…associated with an increased probability of a specific outcome…” “A determinant that can be modified by intervention, thereby reducing the probability of occurrence of …specified outcomes.”

What’s the Greater Risk?

Data Analysis & Interpretation Basic Statistics Rates YPLL Numeric Value Proportions

Data Analysis & Interpretation Basic Statistics Numeric Value – (amount) Easy to understand Does not indicate risk Cannot be compared Very common

Data Analysis & Interpretation Basic Statistics Proportional Distribution - Commonly used Simple calculation Not a measure of risk Sum of all values = 100% Can be misleading 73 % N =225 3 % 14 %

Data Analysis & Interpretation Basic Statistics - Rates “…comparing apples to oranges…”

Data Analysis & Interpretation Basic Statistics - Rates Rate: “An expression of the frequency with which an event occurs in a defined population over a specific period of time and converted to a whole number by multiplying to some power of 10 (usually 10,000 or 100,000).” - A Dictionary of Epidemiology

Data Analysis & Interpretation Basic Statistics - Rates Community A Community B Community C Rate 150 per 100, per 100, per 10, per 100,000

Data Analysis & Interpretation Basic Statistics Rate Number of cases Population at risk (same exposure period) X 10 n or (K)

Data Analysis & Interpretation Basic Statistics Rate 17 Cases 13,000 Population (same time period) X 100,000 Standard Pop. = 131 per 100,000 population

Data Analysis & Interpretation Basic Statistics - Rates Selected Types of Rates Crude Rate Specific Rate Adjusted Rate

Data Analysis & Interpretation Basic Statistics - Rates Rates Accurate numerator Estimated denominator Used primarily for comparison Indicator of risk

Data Analysis & Interpretation Basic Statistics YPLL = Years of Potential Life Lost Measure of Premature Death YPLL = 65 - age at death

Summary Data Analysis & Interpretation Epidemiology serves as a foundation Many data analysis methods Importance of rates Communicate your findings Utilize available resources

Data Analysis Exercise