Evidence Based Practice, encompasses three facets: patient values, clinical expertise and best research evidence.

a descriptive question asks for descriptive information about what is going on - E.g., how many calories do Australians consume per day?

A relational question examines the relationship between two variables, used in observational studies. E.g what is the relationship between me taking modafinil and listening to top 40 music

Causal questions examine if one or more variables cause or affect an outcome.

see below.

A systematic review of an rct is the highest level of evidence (I) and uses several RCTs as its source for information.

An RCT is a randomised control trial, and is a level II type of evidence. They involve a control group, an intervention group and an intervention. RCTs are different from Pseudo-RCTs because true randomisation is involved.

A pseudo randomised control trial is level III-1, it also involves a control and an intervention group, but true randomisation is not involved usually due to ethics.

A cohort study is level III-2, it involves a control group, an exposure group and an exposure. Cohort studies follow participants for a period of time and revisit, case control studies look at the past.

A case control study is level III-3, it involves a control group, an exposure group and an exposure. Cohort studies follow participants for a period of time and revisit, case control studies look at the past.

A cross sectional study is level IV on the hierarchy of evidence, and often conducted using surveys. Cross sectional studies look at a single occasion/day, rather than a period of time. C

A p-value is an indicator of how likely the results are to be caused by chance. A statistically significant p-value is 0.05 or less, meaning there is less than 5% chance of the results being caused by chance.

A correlation coefficient measures how strong the relationship between two variables are. A positive correlation is when two variables move in the same direction (both increase, or both decrease), a negative correlation is when the variables move in opposite directions (one increases and the other decreases or vice versa). The ranges for correlation strength are: (0) = no relationship, (0.01-0.25) = weak relationship, (0.25-0.50) = weak to moderate relationship, (0.50-0.75) moderate to strong relationship, (0.75-0.99) = strong to very strong relationship, (1) = perfect relationship.

An independent variable is a variable that influences the outcome. In an experimental study the independent variable is the intervention, and in an observational study the independent variable is the exposure. E.g in a trial of a new drug, the drug would be the independent variable.

A dependent variable is the outcome, that is influenced by an exposure or an intervention. E.g in a trial for a new drug, the dependent variable is the condition being treated.