Download DHYGN 410 Research Methods

Dental Public Health:
Research Methods for the Dental
Hygiene Student
A Slide Series Review
Why Research?
• Science which can make
diagnosis, treatment, and
prognosis better
• Practice utilized evidencebased theories
• Industry
• Safety
• Others
What is Research?
• Stats
• Rats
• Mazes
Research in Dental Hygiene
Why We Need To Be Educated in
Research Methods
The Debate
• Is dental hygiene a
field of study or a
discipline?
Research in Dental Hygiene
• The greatest value of
research is in its
contribution to the
body of knowledge
that can be used by the
practitioner.
Research in Dental Hygiene
• Why practicing dental
hygienists should get
involved
BS and MS Degrees in Dental
Hygiene
• Where do they fit in?
• Why do they help the
entire profession?
Michaels
• Research and scholarship are not merely activities; they are
a way of life and a way of thinking about life. Research
and scholarship are founded on skepticism, distrust of
authority, constructive criticism, clarity of thinking, trust in
evidence, and recognition that knowledge is tentative,
conditional, and probabilistic. Research and scholarship
require a way of thinking about the world and things in it
that provokes the drive to search for the truth and the drive
to share publicly not only the truth but the methods for
searching for it. The drive to search for the truth, the drive
to share the truth, and the methods of the search are
relentless, uncompromising, and discomforting.
Critiquing Studies and Products
The Art of Criticism
The Art of Criticism
• Location of Published
Material
• Author
• Purpose of the
Publication
• Statement of the
Problem
• Hypothesis
The Art of Criticism
• Purpose: Should explain
what is studied
• Problem: Clearly
identified goal
• Literature Review:
Thorough and current
• Methods: Described
methods utilized, research
designs, and materials to
be used in the study
• Results/Discussion:
Conclusions justifiable
with recommendations for
future studies
The Art of Criticism
•
•
•
•
Assumptions
Limitations
Definitions of Terms
Sample Size and
Technique
• Research Design
• Methods and Materials
The Art of Critism
• Peer-reviewed journal
• Blind review process
• Referred journals
Reviewing the Literature
• What makes a great
article?
• Literature Search
• Reference Books
• Government
Documents
• Periodicals
Literature Review
• Computer Searches
• Locating Articles and
Books
• Organizing the
Material
• Length
• Stumbling Blocks
Biostatistics
Descriptive and Inferential
Measures of Central Tendency
• Mean: The arithmetic
average
• Median: The middle
item of the data set
(midpoint)
• Model: Most
frequently occurring
number in the data set
Measures of Dispersion
• Range: The highest score
minus the lowest score
• Variance: The sum of the
squared deviation of the
sample mean divided by
one less than the total
number of items
• Squared Deviation: The
square root of the variance
Inferential Statistics
•
•
•
•
•
•
•
Parametric
Pearson Product Movement
Spearhman Rho Product Movement
ANOVA
Nonparametric
Chi Square
Others
Depiction of Data
•
•
•
•
•
•
Frequency Tables
Bar Charts
Histogram
Frequency Polygon
Scattergram
Pie Chart
90
80
70
60
East
West
North
50
40
30
20
10
0
1st Qtr
2nd Qtr
3rd Qtr
4th Qtr
Distribution
• Normal Distribution:
a frequency
distribution of scores
that when graphed
yields a bell-shaped
curve.
– Gaussian Distribution
• Skew: extreme scores
that affect the
distribution
Correlation
• Positive linear
relationship: The scores
vary together.
• Negative linear
relationship: The scores
are inverse.
• Perfect or strong
correlation would be close
to +1 or –1.
• No Correlation: Close to
O
P-Values/Statistical Significance
• Significant p-values
indicate that the
association between
the dependent and
independent variables
was not due to random
change. Rare chance
occurrences and
statistically significant
results <.05.
Errors
• Type I Error: Null
hypothesis is false
when it is actually
true.
• Type II Error: Null
hypothesis is true
when it is actually
false.
Sampling Techniques
• Random: Selected
independently with an
equal chance at selection.
• Systematic: Every nth
subject
• Convenience: Selection
from readily available
subjects
• Stratified Sampling:
Delineating subjects into
age, weight, race, etc.
Terms to Review
• Mortality: Deaths from a given disease/condition
• Morbidity: Illness from a given disease/condition
• Prevalence: All existing cases of
disease/condition
• Incidence: New cases of a disease/condition
• Epidemic: A disease/condition among many
individuals at the same time
• Pandemic: Widespread outbreak of a
disease/condition across a region or continent
• Endemic: Low but constant level of a
disease/condition among a population
Terms to Review
• Risk Factors: Characteristics that may increase
the likelihood of disease/condition/health
• Surveillance: Methods of systems used to monitor
health and disease in a population
• Etiology: The study of disease
• Independent Variable: Condition being
manipulated or controlled
• Dependent Variable: Measure thought to change
• Extraneous Variable: Uncontrolled variables that
may affect study
Terms to Review
• Statistically Significant: Obtained result is likely
to be a result of the independent variable.
• Validity: The degree to which the study measures
what it intended
• Reliability: The study could be reproduced and
yield the same results.
• Pilot Study: A small study done prior to a large
study to help set controls
• Placebo: A nontreatment given as an independent
variable, “the sugar pill”
Terms to Review
• Blind: Subject does not know whether he/she is
receiving treatment.
• Double blind: The researcher and subject do not
know whether subject is receiving treatment.
• Cross-over: Subject is tested on two different
treatments at different times.
• Wash-out: Subject has a period of no treatment
during the crossover.
• Split-mouth: Half of the mouth is used for
treatment, the other half as a control.
Terms to Review
• Longitudinal Study: An investigation over a long
period of time
• Prospective Study (Experimental): Clinical trials
• Retrospective Study (Ex Post Facto): Looks at
population with disease/health in the past
• Epidemiological Study: Study of the factors
causing disease/conditions/health
• Descriptive Study: Involves description, analysis,
and interpretation of current conditions
• Case Study: Intensive investigation of a person,
family, or small group in a natural setting.
Summary
• Understanding the
concepts of research is
necessary for the
practicing dental
hygienists.