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DESCRIPTIVE
RESEARCH
Chief characteristics
• Due to the nature of the classification
variable (i.e., a subject variable),
extraneous variables affecting the
classification variable cannot
be
controlled;
• However, extraneous variables affecting
the
measurement of the criterion
variable can usually be controlled,
although this may not be desirable for
very high external validity;

Slide 1

• No manipulation of independent variable;
• Subject groups are not the result of
random assignment, through they may be
designated through random selection;

Slide 2

• Aims to examine:
1.
2.
3.
4.

differences between groups
relationships among variables
trends (changes over time)
status or level of a variable

• Relative to experimental research,
internal validity is low, while external
validity is high;
• Research hypothesis may be of less
importance - descriptive research often
aims to generate hypotheses which may
then be experimentally tested;

Slide 3

• Data may be quantitative or qualitative
and may not be amenable to statistical
analysis.

Descriptive research "attempts to
provide an accurate description of
a particular situation ... to identify
the variables that exist in a
situation/to
describe
the
relationships existing between
(among) these variables."
from Christensen, Experimental Methodology

Slide 4

VARIABLES
Independent variable
In experimental research, the researcher
manipulates the I.V., i.e., applies or
withholds it; varies its level; etc.

Dependent variable
The
variable
measured
experimenter in order to detect

by

the

Classification variable
In descriptive research, subjects are
classified according to the classification
variable, e.g., by sex, age, disorder,
etiology, etc.

Slide 5

Criterion variable
The classified subjects are compared
according to some criterion, e.g., rate of
learning, hearing threshold, vocabulary
age, etc.
In descriptive research, the classification
variable is analogous to the I.V. of
experimental research, and the criterion
variable to the D.V. Some researchers
prefer to use I.V. and D.V. instead even in
descriptive research.

Slide 6

Predictor and predicted variables
In correlational studies, analogous to
I.V./classification variable.
In such
studies, the predictor variable is used to
predict the behavior of the D.V./criterion
variable, which is designated the predicted
variable. E.g., an auditory discrimination
measure may serve as a predictor variable
for an articulation measure, the predicted
variable.

Slide 7

DESCRIPTIVE
RESEARCH
Principal types
Comparative
Aims to measure the behavior of a
criterion variable at a single point in time
in order to draw conclusions about
similarities or differences between the
classification variables (i.e., between the
populations).

Correlational
Aims to measure the degree to which a
predictor and predicted variable are
associated/related, i.e., the degree to
which changes in the predictor
correspond to changes in the predicted.
Slide 8

Developmental
Aims to measure changes over time
(trends) in the criterion variable (e.g., due
to ageing, maturation, recovery, learning,
etc.).
Longitudinal
Studies one group of subjects over a
prolonged period of time.
Cross-sectional
Studies two or more groups of subjects,
each of which is at a different, progressive
level (i.e., age, stage of recovery or
learning, etc.).

Slide 9

Descriptive
Aims to ascertain the level or status of a
criterion variable at a specific point,
without comparison of groups, or of stages
of development (= description only).

Slide 10

SYSTEMATIC OBSERVATION
Steps
1. Choose the criterion variable (i.e., a
natural behavior).
a. specific
b. unambiguous
2. Select setting
a. where criterion variable can be
expected
b.
where observer can remain
unobtrusive

Slide 11

3. Decide on mode of recording
a....
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