a philosophy of events and nature that values evidence more than opinions. It is conceptual and philosophical
is waht scientists do as they practice science. It is the process of asking and answering questions ; it includes steps scientists take as they search for uniformity and order in nature. it is methodological. It is basically science in action!
the philosophical position that statements must be supported by experimental or observational evidence
The goals of science are to (Hedge, 2003; Maxwell & Satake, 1997)
1. describe natural events or phenomena
2. understand and explain natural phenomena; especially in terms of cause-effect relationships
3. predict occurrences of events; and
4. control natural phenomena by understanding the causes of events and predicting their occurence
an experiment first- and - explain later approach
A scientist would experiment first and then propose a theory based upon the results of the experiment
A scientist will propose a theory first and then verify it.
a systematic body of information concerning a phenomenon, describing an event, explaining why the event occurs, and specifying how the theory can be verified causable variables; a theory states that X causes Y
concerned with more specific prediction stemming from a theory. it is a proposed answer to a specific question. They are testable propositions derived from a theory.
alternative hypothesis state
that the 2 variables are indeed related; perhaps one is the cause of the other
The researcher hopes to
reject the null hypothesis and accept the alternative hypothesis because the research often believes in the alternative hypothesis
scientific data should meet two criteria
validity and reliability they are critical aspects of scientific measurement
predictive validity/criterion validity
is the accuracy with which a test predicts future performance on a related task.
ex. a graduate student's score on a comprehensive exam might predict whether or not he or she will be a competent clinician
considered a form of criterion-related validity, ist he degree to which a new test correlates with an established test of known validity
is the degree to which test scores are CONSISTENT with the theoretical constructs or concepts
a measure of test validity based on a systematic examination of all test items to determine if they adequately sample the full range of the skill being tested and if they are relevant to measuring what the test purports to measure.
refers to the consistency with which the same event is measure repeatedly. most are expressed in terms of correlational coefficient
is a number or index that indicates the relationship between two or more independent measures. usually expressed through Pearson Product moment r
refers to consistency of measures when the same test is administered to the same people twice. When the two sets of scores are positively correlated, the stability of the scores over time is assumed
alternate from reliability/parallel from reliability
is based on the consistency of measures when two parallel forms of the same tests are administered tot he same people.
a measure of internal consistency of a test. It is determined by showing that the responses to items on the first half of a test are correlated with responses given on the second half. It generally overestimates reliability because it does not measure stability of scores over time.
interobserver or inerjudge reliability
refers to the extent to which two or more observers agree in measuring an event. Ex. if 3 judges independently rate the fluency of a subject, there is high interjudge reliability if there is good agreement between he judges.
intraobserver or intrajudge reliability
refers to the extend to which the same observer repeatedly measures the same event consistently. Ex. if the same clinician rate a child's intelligibility over several sessions, those ratings would be consistent if there is good intraobserver reliability.
is directly manipulated by the experimenter. The manipulation causes changes in the dependent variable. All treatments are independent variables
dependent variable or effect
is the variable that is affected by the manipulation of the independent variable. In treatment research, all disorders are dependent variables (disorder or particular skill) they must be defined good so that they are measurable
experimental will consist of
two or more groups. It contains participants who receive treatment and thus show changes in behaviors treated
contains participants who do not receive treatment. The goal of having these tow groups is to demonstrate that the experimental participants improved and the control participants did not, thus showing the efficacy of the treatment
pretest-posttest control group design
there are two groups; an experimental group and a control group. This design is to evaluate the effects of a single treatment
multigroup pretest-posttest design
it evaluates the relative effects of two or more treatments. A question of relative effects asks: Which treatment is more effective? An investigator randomly selects a sample from a population and randomly assigns them to one of the three groups. they each receive a different treatment
a major limitation of true group experimental designs is that
it is not always possible to randomly draw participants from specific clinical populations.
a major limitation of group experimental designs is that
they may not allow extension of the study's results t the individual clients.
single subject designs
are playing an increasing role in establishing efficacy of treatment procedures used in speech. These designs help distinguish cause-effect relations based on individual performances under different conditions of experiment.
The ABAB design
A) condition refers to baseline
A) condition refers to treatment withdrawal
B) reinstatement of the treatment
mulitple baseline deisngs
a single subject design that aids the disadvantage of treatment withdrawal. the effects of treatment are demonstrated by showing that untreated skills did not change and only the treated skills did. . it is across subjects, setting, and across behaviors
ex post facto research
is after the fact research. the investigator begins with the effect of independent variables that have occurred in the past. Thus the investigator is making a retrospective search for causes of events (Hegde, 2003)