Praxis Chapter 14 (Research)

science

philosophy of events and nature that values evidence more than opinions
-use objective, experimental methods to systematically investigate research questions
-produce valid and reliable results that help answer them

research

what scientists do as they practice science
- science in action
- process of asking and answering questions
- includes steps scientists take as they search for uniformity and order in nature

science

conceptual and philosophical

research

methodological

empiricism

the philosophical position that statements must be supported by experimental or observational evidence
- evidence is typically sensory experience that must be objectively verifiable
- permit observation and measurement

determinism

events do not happen randomly or haphazardly
- caused by other events
- scientific activity based on determination is a search for causes of events

1. describe
2. understand and explain
3. predict
4. control

goals of science

1. inductive methods
2. deductive methods

scientists may use one of two approaches to explain events:

inductive method

an experiment-first-and-explain-later approach
- observes the phenomenon
- conducts a series of experiments on it
- proposes a theory based on the results of those experiments

deductive method

an explain-first-and-verify-later approach
- based on initial observations
- investigators explain an event by proposing a theory and then attempt to verify the theory by conducting experiments
- hypothesis - testing

theories

scientists use inductive and deductive reasoning to build _____________

theory

systematic body of information concerning a phenomenon
- describing an event
- explaining why the event occurs
- specifying how the theory can be verified
- specifies causal variables
- a states that X causes Y

hypothesis

proposed answer to a research question, but verifiable through additional research
- concerned with a more specific prediction stemming from a theory

null hypothesis

states that two variables are not related
ex: stressful situations and stuttering are not related, that when people who stutter are placed in highly stressful speaking situations, stuttering does not increase

alternative hypothesis

states that the two variables are indeed related
- perhaps one is the cause of the other
ex: highly stressful speaking situations do cause an increase in stuttering

data

result of systematic observation (experimentation)
- gather _____ by testing the hypothesis
- observe events and record some measured values of those events

scientific data

empirical, meaning that they are based upon actual events that resulted in some form of sensory contact

qualitative data

verbal descriptions of attributes of events
- stated in words

quantitative data

numerical descriptions of attributes of events
- given in numbers

1. validity
2. reliability

scientific data should meet two criteria:

validity and reliability

critical aspects of any type of scientific measurement
- including measurement through standardized tests
- clinical measurement of the client's skills
- standardized and nonstandardized tests

reliability

Refers to the consistency of scores across repeated testing

interobserver reliability

same results no matter who gives the test
Ex. Examiners marking school and university exams are assessed on a regular basis, to ensure that they all adhere to the same standards

intraobserver

same person who gives the test, same results
Ex: A doctor with good intraobserver skills would read a patient's x-ray results the same way weeks later.

test-retest reliability

if it is given repeatedly to a client, it should yield similar results from one trial to another
Ex: A test of color blindness for trainee pilot applicants should have high test-retest reliability, because color blindness is a trait that does not change over time.

alternate form reliability

consistency even if there are different forms
administered (Form A and B or Test 1 and 2)
Ex: A person is asked to fill a questionnaire to conduct a personality test. A month later, the person is given the same form to fill with some of the questions rephrased. If the responses of the person vary wildly we conclude that the questionnaire does not have alternate form reliability. This means that there is some mistake in the way the questionnaire was designed by the researcher.

split-half reliability

first and second half are compared
Ex: A group of subjects is split into half. Half take the first part of the test and half take the second. You compare the results to see if there is a consistency in the level of questions in the test.

validity

The degree or extent to which the test measures what it is supposed to measure

concurrent validity

the degree to which a new test CORRELATES with an established test of known validity
Ex: if you gave a new articulation test, would the results be similar to that of the known GFTA test

construct validity

the degree to which test scores are CONSistent with theoretical concepts
Ex: test scores should be higher on a language test for older kids than younger kids and if the test shows this then it is consistent with a known theory of language development

content validity

the degree to which a test items actually measure the skills targeted and that it measures the skill adequately
Ex: a test of articulation should include all speech sounds

predictive validity

the degree to which the test PREDICTS future performance on a related task
Ex: a score on a language test may be predictive of success academically

descriptive research

researchers observe phenomena of interest and record their observations
- do not want their presence to interfere with the natural phenomena that are being observed
- cannot lead to cause-effect statements

types of descriptive research

1. ex post facto research (retrospective research)
2. survey research
3. comparative research (standard-group comparisons)
4. developmental (normative) research
5. correlational research
6. ethnographic research

1. classification variable
2. criterion variable

two types of variables in descriptive research

classification variable

analogous to the independent variable in experimental research
- unmanipulated

criterion variable

analogous to the dependent variable in experimental research

descriptive research

____________ is useful when it would be unethical to use experimental methods and understand a phenomenon
- helps us understand what already exists

experimental research

permits us to actively manipulate conditions to change what exists

ex post factor research

after-the-fact research (retrospective research)
- causal-comparative studies
- begin by defining the effect as it currently exists
- they then look backward in an effort to describe potential cause or causes

ex post facto

investigations into potential causes of disorders or diseases
- investigate the potential causes

prospective research

ex: smokers who do not have lung cancer may be followed up for a decade to see how many develop that type of cancer

limitation of ex post facto research

can only suggest, but not confirm, causes of disorders and diseases

usefulness of retrospective studies

help investigate phenomena that are not amendable to experimental manipulation at the human level
ex: researchers would not ask some people to smoke and others not to and then observe over the years to see if those who smoked developed lung cancer

surveys

assess some characteristics of a group of people or a particular society
-attempt to discover how variables such as attitudes, opinions, or certain social practices are distributed in a population
- randomly selected

1. questionnaires
2. interviews

most common types of survey research tools

personal interviews

help obtain in-depth answers from survey participants

questionnaires

filled out by survey participants may yield a greater quantity of responses, but those responses may not contain the depth of those given in interviews

advantage of surveys

wide range of data can be obtained

disadvantages of surveys

- they cannot be used to illustrate cause-effect relationships
- their samples are often biased because those who return surveys may not be comparable to those who do not

comparative research

standard-group comparison
- measure the similarities and differences of groups of people with defined characteristics
ex: attention and memory skills of people with head injury may be compared and contrasted with those of individuals without head injury

disadvantage of comparative research

the similarities and differences found between groups of individuals might be due to variables other than the classification variable

developmental research

to measure changes in individuals over time as they mature or get older
- the presumed variable is maturation
- create developmental norms
- normative research

maturation

age is the cause of changes seen in people, especially developing children

normative research methods

have been used extensively to establish age-based norms on children's speech sound and language skills
- used to study the cognitive skills of older adults as they continue to age

1. longitudinal research
2. cross-sectional research
3. semi-longitudinal research

3 methods used in developmental (normative) research

longitudinal research

the same participants are studied over time to observe the changes that occur within them as they get older
- often have small numbers of participants
- limiting the generalizability of the results

advantage of longitudinal research

the investigator can directly observe changes in such behaviors as language skills or fluency in the same participants as they get older

disadvantages of longitudinal research

1. time-consuming
2. expensive
3. vulnerable to subject attrition

cross-sectional method

researchers select participants from various age levels and simultaneously or within a short duration of time sample the behaviors or characteristics of the groups formed on the basis of age

advantages of cross-sectional method

1. cheaper
2. faster
3. more practical than longitudinal research

disadvantages of cross-sectional method

what is observed for a particular age group in the study may not hold goods for others of the same age who are not in the study

semi-longitudinal procedure

the total age range to be studied is divided into several overlapping age spans
- participants selected are those who are at the lower end of each age
- are followed until they reach the upper end of their age

correlational research

tries to find relationships or associations between variables
- cannot uncover cause-effect relations
- events studied are related, but whether there is a cause-effect relation would not be clear

correlation

a statistical method of data analysis suggesting that two or more events are somehow associated or related
- suggests the direction (positive or negative) and the strength (high or low) of the relationships

positive correlation

found when high values of one variable predict high values of the other variable
- when one event increases, the other event increases
ex: temperature increase / sales of ice cream increases

negative correlation

found when high values of one variable are associated with low values of the other variable
- when one event increases, the other event decreases
ex: increased pressure to communicate may decrease a speaker's fluency

stronger and more positive the relationship

closer a number is to +1.0

stronger and more negative the relationship

closer a number is to -1.0

weaker the relationship

closer a number is to 0

ethnographic research

observation and description of naturally occurring phenomena
- included under the aegis of descriptive research
- not an experimental type of research
- originally designed by anthropologists as a means of conducting in-depth analytical descriptions of cultural scenes
- study existing phenomena without altering them

qualitative research

ethnographic research is _____________
-external verbal descriptions

experiment

means of establishing cause-effect relationships
- test if-then relationships

independent variable

directly manipulated by the experimenter to produce changes in a dependent variable
ex: treatments

dependent variable / effect

the variable that is affected by manipulation of the independent variable
- manipulation of treatment changes the ___________
- must be defined very specifically so that they are measurable
ex: all disorders

extraneous / confounding variables

ruled out in experiments
- study conditions are carefully controlled to eliminate the influence of unwanted variables

1. group designs
2. single-subject designs

types of experimental designs used in SLP

group designs of research

the average performance of one group is analyzed or those of two groups are compared
- may be experimental or nonexperimental

nonexperimental group research

consist of only one group

experimental group research

consists of two or more groups

experimental designs

using groups to rule out the influence of confounding (extraneous) variables through the use of experimental and control groups

experimental group

receives treatment and thus shows significant changes in behaviors trated

control group

does not receive treatment and does not show improvement

goal of experimental and control groups

demonstrate that the treatment is better than no treatment
- an essential condition to show that the treatment was effective

randomization

one method of forming two or more groups for a study
- randomly selects a sample from the population
- has an equal chance of being selected for the study

population

large, defined group identified for the purpose of a study
ex: people who study

sample

smaller set that is representative of the population

randomly assigned

randomly selected sample participants are then __________ to treatment and control groups
- each selected participant has the same chance of being selected for one or the other groups

matching

an alternative to random selection and assignment
- first identify two participants who are similar on relevant variables and then assign one to the experimental group and the other to the control group
- ensures that those who receive treatment and those who do not are similar kinds of participants

pretest-postest control group design

the basic experimental group design to establish causality
- has 2 groups:
1. experimental group
2. control group
- helps evaluate the effects of a single treatment

pretests

participants' existing behaviors or skills measured before starting an experimental treatment or teaching program

posttests

measures of behaviors established after completing the treatment program

comparison of pretests and posttests

helps demonstrate the effects of treatment while ruling out the influence of confounding variables by showing that only the treated group changed and the control group remained at or close to the pretest

multigroup prettest-posttest design

helps evaluate the relative effects of two or more treatments
- each treatment requires an experimental group
- helps evaluate relative effects of 3 treatments
- participants are selected and assigned randomly
- each group receives a different treatment

question of relative effects

Of the two or more, which treatment is more effective?

advantages of group experimental designs

- true experimental designs are the most powerful of the group design strategies
- useful in isolating cause-effect relationships between variables
- strong internal validity

disadvantages of group experimental designs

- it is not always possible to randomly draw participants from specific clinical populations to which clinicians do not always have access
- results may be extended to groups but not individual clients

single-subject designs (SSDs)

playing an increasing role in establishing the efficacy of communication treatment procedures
- help establish cause-effect relations based on differential performances under different conditions of an experiment
- allow extended and intensive study of individuals and do not involve comparisons based on group performances

characteristics of SSDs

1. measure the dependent variables continuously and repeatedly to establish their reliability
2. most have multiple participants
3. experimental

AB design

single-subject design
- not experimental and similar to a case study
A = routine clinical work in which the baselines are established
B = treatment is offered