Research Design

Question 1

What the difference between Research and Evidence?

Answer 1

-Research is results from individual studies, whereas evidence is an
accumulation of results across studies

-Evidence is the synthesis of all valid research studies that answer a specific
question

-Evidence-based practice involves tracking down available evidence, assessing
its validity, & using the best evidence to inform treatment decisions

Question 2

What is Validity?

Answer 2

closeness to the truth; degree to which design & method provide accurate
investigation of event in question

Question 3

What is Internal Validity?

Answer 3

(selection, maturation, instrumentation)

Are the results valid for the patients in the study?

Was the study performed correctly?

Was any difference
between groups seen?

Threats (yikes):

Selection bias: sample is collected where some members of the intended population are less likely to be included

Question 4

What is Maturation?

Answer 4

Wrong age group or it ages out

Question 5

What is Instrumentation?

Answer 5

How you measure, are you doing it appropriately?

Question 6

Random assignment to groups addresses many threats to internal validity but….

Answer 6

not all!

Question 7

What is External Validity?

Answer 7

(publication, financial)

Ability to generalize findings: beyond subjects in the study, beyond environmental
constraints of current study and to other temporal periods

Are the results valid for patients not involved in the study?

Does the study population represent the larger group?

Question 8

As controls increase (increasing internal validity)….

Answer 8

the generalizability of findings may suffer (decreasing external validity)

Threats: Publications & Financial

Question 9

Quantitative data (numbers) vs. Qualitative data (interpret)

Answer 9

Inquiry rooted in empiricismbased in hermeneutics
Only measurable phenomena is real Interpretation/contextual

Measures often numeric scales meaning
Subjective measures dependent on perceptual biases

Question 10

What are tests for Data Examples?

Answer 10

Chi-square for nominal/categorical data

Mann/Whitney for ordinal data (severity of perio-disease)

T-tests or ANOVVA for continuous/interval or ratio data (pocket depth)

Question 11

Systemic Reviews vs. Meta Analysis:

Answer 11

-Systematic review is formal approach to review all relevant literature on a topic..

whereas meta-analysis..

is a statistical method used to combine the numerical results
from such studies, if possible to do so. Systematic reviews often include a meta-
analysis

Question 12

What are Randomized Control Trials?

Answer 12

Strongest evidence for demonstrating causes and effect
Reduces effect of bias due to intervening variables
Assumes that confounding conditions will be equally distributed among groups

Question 13

What do Randomized Control Trials include?

Answer 13

● At least one “varied condition” (treatment vs no treatment)

● Concurrent enrollment

● Random assignment to groups

● Follow up

Question 14

What does Blinding do?

Answer 14

Blinding attempts to reduce bias due to expectations or preconceptions of
patients or investigators (double blind)

Question 15

Describe Experimental Research:

Answer 15

Quantitative

Investigates cause

Controls or manipulates variables under investigation

Question 16

Describe Observational Research (Cohort & case control studies):

Answer 16

Quantitative or qualitative

Without experimental controls (may include comparison of natural group)

“Quasi experimental”

Investigation of relationships, but not cause

i.e. researcher investigates relationship between smoking and lung cancer
(considers exposure and outcomes instead of testing an intervention like a drug)

Question 17

What are examples of Variables?

Answer 17

Any factor relevant to particular study; may be known or unknown; examples → age,
SES, ethnicity, disease history

Question 18

What are Independent Variables (changes) vs. Dependent Variable?

Answer 18

Independent =Variable:
Factor changes naturally, Observed variable in a study.
=Intentionally Manipulated, Changes determined by level

> > ???
Grouping variable of independent variable(s)
Known & controlled by experimenter Factor directly affected by
“Causative factor”another factor
“Response” or “outcome

Question 19

What are Confounding Variables/

Answer 19

Error- not measured by researcher and has impact

Extraneous variable correlates w/ both D & I variables

Factor not considered by researcher that has significant impact on the dependent
variable or outcome of interest

“Confounding influences” or “error”

Question 20

What is the Difference between Prospective vs. Retrospective Research?

Answer 20

● Prospective: looks at events that haven’t happened yet or constructs that have
not yet been measured

● Retrospective: looks at data that already exists

Question 21

When appraising a study, what should you pay close attention to?

Answer 21

When appraising a study pay close attention to descriptions on selection and
assignment process of participants and other factors like hypotheses, intervention&raquo_space;>assessment, & data analysis«