Evidence Based Medicine

Evidence Based Medicine

Week 2: Basic Research Concepts in Western and

Eastern Medicine

What is Research?

A process of discovering new information.

“A systematic investigation ( i.e., the gathering and analysis of information) designed to develop or contribute to

generalizable knowledge.”

The Scientific Method

Steps to Research

1. Developing a statement of the research question

2. Developing a statement of the research hypothesis

3. Defining the “instrument” (questionnaire, unobtrusive measures)

4. Gathering the data 5. Analyzing the data 6. Drawing conclusions regarding the

hypothesis.

Research Question vs. Hypothesis

Research Question is a clear statement of what you want to know. Important to be precise to make the data you gather as

useful as possible!

Hypothesis is a statement of some idea of how events and variables are connected – this is a predictive statement which you will

either prove or disprove via the actual study. *This is what you think is going to

happen.

For both it helps to be specific

Research Design“provides the glue that holds the research project

together. A design is used to structure the research, to show how all of the major parts of the research project work together to try to address the central research questions.”

The information collected during research is only useful if the research design is sound and follows the research protocol.

Following the research protocol and thus the design of the study is also important because the results can then be reproduced by other researchers. The more often results are reproduced, the more likely it is that researchers and the public will accept these findings as true.

Defining the InstrumentInstrument refers to instrument with which

you are measuring variables.

In TCM studies it could be a patient questionnaire, lab values, biological samples, test (i.e. of cognitive function) objective measures such as blood pressure or weight, subjective measures such as pain ratings.

The more objective, precise and repeatable the instrument is, the more valid the research becomes.

Variables and Observations

Variable refers to some specific characteristic of a subject that assumes one or more different values. (insurance sold, goals set)

A value refers to the amount of that variable (i.e. 5 years is the value of the variable 'age')

Quantitative variables. They are variables in which numbers serve as values.

Classification variable, also called a qualitative variable or categorical variable. Different values represent different groups. (gender, race) These variables only represent group membership; they do not represent a characteristic that some subjects possess in greater quantity than others.

Observational units (or observations), which can be defined as the individual subjects (or other objects) that serve as the source of the data. The number of subjects who were studied

Types of Studies

Descriptive Study – Also called Correlational, Observational, Nonexperimental or Nonmanipulative

Experimental Study

Descriptive Study Information is collected without changing the

environment

Descriptive studies can involve a one-time interaction with groups of people (cross-sectional study) or a study might follow individuals over time (longitudinal study)

Descriptive studies can provide information about the naturally occurring health status, behavior, attitudes or other characteristics of a particular group. Descriptive studies are also conducted to demonstrate associations or relationships between things in the world around you.

These types of studies are often done before an experiment to know what specific things to manipulate and include in an experiment.

Bickman and Rog (1998) suggest that descriptive studies can answer questions such as “what is” or “what was.” Experiments can typically answer “why” or “how.”

Descriptive Study Cont...A response variable is an outcome variable or

criterion variable, whose values you want to predict from one or more predictor variables. The response variable is often the main focus of a study because it is mentioned in the statement of the research. (Dependent variable in experimental research)

A predictor variable is the variable used to predict values of the response.(Independent variable in experimental research)

Notice that nonexperimental research, which investigates the relationship between just two variables, does not provide evidence concerning cause-and-effect relationship

Experimental Study A treatment, procedure, or program is

intentionally introduced and a result or outcome is observed.

“A test under controlled conditions that is made to demonstrate a known truth, to examine the validity of a hypothesis, or to determine the efficacy of something previously untried.”

True experiments have four elements: manipulation, control, random assignment, and random selection.

Experimental Study Cont... Manipulation = something is purposefully

changed by the researcher in the environment.

Control = prevents outside factors from interfering (controlled for weight/age/ whatever) – minimizes error and bias

Random assignment = participants are randomly assigned to groups

Random selection = method of sampling where research participants are selected from a larger group by chance – this is very rarely the case in medical research

Experimental Study Cont... An independent variable is that variable whose

values (or levels) the experimenter selects to determine what effect this has. The independent variable is the experimental counterpart to a predictor variable. *This is what you manipulate

A dependent variable is some aspect of the subject’s behavior assessed to reflect the effects of the independent variable. The dependent variable is the experimental counterpart to a response variable. *This is what changes

Researchers often refer to the different levels of the independent variable. These levels are also referred to as experimental conditions or treatment conditions and correspond to the different groups to which a subject can be assigned.

Association The term association means that two or

more things are related or connected to one another like height and weight, cholesterol level and heart failure or exercise and weight.

Positive associations suggest that when one variable is increased, the value of another variable increases (height and weight)

Negative associations mean that when a variable is increased, the value of another variable decreases (exercise and weight)

Cause and Effect NOT the same as association. Just because weight usually increases

with height doesn't mean height CAUSES weight.

Likewise the association between weight loss and exercise is just an association until you do an experimental study to determine if it is actually a cause.

***This messes up medical researchers all the time. We mistake association for cause, which leads to treatment errors. *cholesterol is the perfect example

Blinding Blinding is a technique used to decrease

bias on the part of the researcher or the participant. In some studies, the

Single blind = participant is not told to which group they have been assigned.

Double blind = neither participant nor researcher know the group to which the participant is assigned.

The gold standard for medical research is double blind, placebo controlled.

Information Gathering Three major concepts are important to

understand in order to collect useful and valuable research information:

Precision/Reliability = Method measures the same thing every time you use it. (Environment, social cues, timing all influence)

Accuracy/Validity = Your instrument really measures what you think it measures (multiple instruments solves this problem)

Error = something is going wrong somewhere.

Error This doesn't usually mean gross mistake.

It's more subtle than that. Random Error. An error is considered

random if the value of what is being measured sometimes goes up or sometimes goes down. (i.e. blood pressure readings – inexplicable fluctuations)

Systematic Error. An error is considered systematic if it consistently changes in the same direction. (i.e. calibration error, or blood pressure – white coat syndrome). Measurement is precise, but still not accurate

Human Concerns Ethics IRB – Institutional Review Board Privacy Safety and Security (confidentiality) of

information Informed consent (just like with patient

care)

Results Accurate, transparent documentation

helps to validate research Excluding information is only appropriate

in certain circumstances (i.e. written-in answer to multiple choice question, or unrelated information that came up by chance)

Changing information is never appropriate and always damages the credibility of the research.