Research Cheat Sheet

Research

In Experimental Research, the researcher manipulates an IV (while controlling for potential EV) to examine what effect the manipulation has on DV. To establish a functional relation between the IV and DV.

Hypothesis

Null Hypothesis - no relationship between variables
- no difference in IQ between people between with X and Y
Directional Hypothesis - we state the direction of the relationship between two variables
- X will have higher scores than Y on IQ tests
Non-directional hypothesis - we don't know and won't speculate about the direction of the relationship between two variables
- There will be a difference in IQ scores between X and Y

IRB

ethical research when using humans as subjects
types of research that need IRB
- biomedical
  - biology
  - drugs
  - devices
- behavioral
  - surveys
  - experiment
  - questionnaires
  - all other types of human subject research
key elements of informed consent
- explanation of procedurees
- risks or discomforts
- benefits
- confidentiality
- termination of participation
- costs/compensation
- questions/contact information
- signatures and copy

Qualitative vs Quantitative

Qualitiative
- open ended observation to obtain naturalistic data
- DESCRIPTIVE overview of data/observation
- SMALL sample
- in-depth description of data/observation
- finding themes, patterns and relationships
- understand perspective: WHY a particular outcome
- SUBJECTIVE
Quantitative
- time tested research method
- observations are MEASURED and EXPRESSED in NUMERICAL values
  - objective
  - systematic process
    - numerical dat is used to test the hypothesis
  - LARGE sample
- statistical analyses of numerical data
- understand cause-effect relation; WHAT causes an outcome
- OBJECTIVE

Questions

What is the statement of the general problem? Is it justified with current literature?
Was the rationale for study logical and convincing? Give one reason why you think so
Did authors proved current, thorough, and accurate literature review?
State the aim/purpose and research questions/hypotheses of the study. What is your opinion of the research question?
Was the introduction clearly written and well organized? What would you change?

Research Design

specific plan for selecting the IV(s) & measures to assess the DV(s) in order to answer specific research questions about their relations
Two purposes of a design
- To permit investigator to answer research questions
- To control extraneous variance/noise (variables that could affect the outcome of the study)
Major Classification of Research Designs
- Single Subject Designs (SSD) - purpose is to demonstrate a functional relationship between an INTERVENTION (IV) and a change in target behavior (DV)
  - behavior of one or few individuals is studied
  - each person's performance evaluated in detail to examine affects of IV on DV
  - repeated, systematic measurement of DV
    - before, during, after manipulation of IV
    - DV is usually a human characteristic/behavior
    - IV usually involves application of intervention
  - Types of SSD
    - A-B design
      - used to quickly assess the effects of a treatment
        phase 1 (A)
        measure baseline response
        phase 2 (B)
        introduce treatment while measuring response
        Baseline - Intervention
        get a baseline for trial 1 - 5 and then see what happens at interventional stage
        like monitoring, trials at baseline and then a measured response after a change is made
        can have a delayed effect
        effect happens after many trials
        an immediate effect
        happens right after baseline trials
        small effect or large effect
        variable baseline and intervention
        jagged, all over the place
        stable baseline and intervention
        large jump to intervention then stable
        combined effects
        baseline trend = intervention trend
        basically linear; x = y, y = x
        baseline trend does not = intervention trend
    - Withdrawal Designs
      - A-B-A
        simplest of single subject designs
        repeatedly introduces and withdraws treatment
        A - Baseline phase
        B - Treatment phase
        A - Withdrawal phase
        Objective
      - A-B-A-B
        most powerful demonstration of causality and functional relationship
        withdrawal phase allows more reliable assessment of intervention effects
      - A-B-A-C
    - Multiple Baseline Designs
    - Multiple Treatment Design
- Group Designs
  - Study one or more "large" subject groups to examine affect of IV on DV
  - Compare "average" performance
  - Between - Subjects Design - Treatment Based Design
    - primary purpose is to examine the effect of the IV on two or more groups of subjects
    - with intent to determine whether groups perform similarly or not
    - treatment research with a control group
      - experimental (target) group receives treatment
      - control group does not receive treatment
    - Experimental
      - experimental research comparing the performance of two or more groups on one experimental task or condition
        example: do typically developing children and children with hearing impairment with hearing aids differ in their speech recognition
        example: comparing young vs old in some aspects of hearing/listening skills
  - Within - Subjects Design
    - purpose: compare the performance of a single group on 2 or more conditions
    - all subjects in the study receive all treatments or levels of a treatment
    - also called repeated measures design
    - the main advantage over the between subject design is that it requires fewer participants, making the process much more streamlined and less resource heavy
    - example: does the speech intelligibility or pre-school hearing impaired kids improve comparably after receiving phonological treatment one and phonological treatment two
    - example: does speech perception better in BTE than CIC in the presence of wind noise?
    - experimental design
      - all subjects receive all experimental tasks and/or all levels of one or more of the experimental tasks
      - example 1: development changes in ABR/OAE in children longitudinal or cross-sectional study
      - example 2: does the comprehension of oral directions differ as a function of input speech rate (slow, normal, fast)
  - Mixed - Subjects Design
    - studies that combine both between-subjects design component (have 2 or more groups) and within-subjects design component (all subjects in all groups receive all conditions or tasks in the experiment)
      - make comparisons between subjects/groups (is there difference between groups on task conditions)
      - make comparisons within subjects/groups (how do subjects within each group perform on each level of the IVs)
      - Mixed Subjects Studies can be
        transmission studies
        experimental (non-treatment) studies
Validity in Research Design
- internal validity
  - internal validity is the confidence that we can place in the cause and effect relationship in a study
  - could there be an alternative cause that may explain my observations
- external validity
  - external validity is the ability of the study to generalize
  - whether results obtained from a small sample group, often in laboratory surroundings can be extended to make predictions about the entire population
Counter balance
- to minimize carryover effect/order effect
- order in which the treatment or experimental conditions are administered
- not practice if you have > 5 conditions: expensive and very time consuming

Research Strategies

Descriptive research
- naturalistic/observational
  - no intervention in study, does not manipulate or control anything
  - simple observation
  - no manipulation of independent variable
- survey research
  - asking rather than observing
  - obtain information about opinions
  - questionnaire
- retrospective research
  - obtaining data from already existing clinical data/records
  - no direct experimental manipulation
Experimental research
- bivalent experiments
  - study the effects of two values on one IV on DV
- multivalent experiments
  - study the effects of several values of IV on DV
- parametric experiments
  - simultaneous effect of more than on IV on DV
  - example: study the speech of hearing impaired listener would have to consider
    - level of background noise
    - distance between talker and listener
    - acoustic character of talkers speech
    - type and severity of hearing loss
    - amplification properties of HA
Combined experimental & descriptive
Correlation research
- purpose is to investigate relations between/among 2 or more variables by measuring how changes in one variable (X) corresponds to another (Y)
  - three possible outcomes
    - positive correlations
      - both variables increase or decrease at the same time
    - negative correlations
      - indicates that as the amount of one variable increases, the other decreases (and vice versa)
    - no correlation
      - indicates no relationship between the two variables
- CAUTION 1 - Correlation does not imply causation
  - if 2 variables are correlated it means there is an association, not necessarily a causal association
    - Home Computer -> Child's vocabulary
- CAUTION 2 - "significant" correlations may be due to uncontrolled variables
  - association between X and Y may be spurious (lucky) because another variable may be responsible for moderating the association between X and Y
    - association between home computer use and vocabulary may be due to various other factors like parent education

Scale

Nominal
Ordinal
Interval
Ratio

Variables

anything that can be varied
Independent Variable - variables manipulated by the experimenter
- experimental group (drug) vs control group (placebo)
- hearing aids vs no hearing aids
- slow stimulation rate vs fast stimulation rate
- CAUSE
Dependent Variable - variables that respond to experimental manipulation
- static admittance
- speech in noise performance
- wave V latency
- EFFECT
Extraneous Variable - aka nuisance variable
- Testing environment
- Instructions
- Monaural vs Binaural
- Age
- Motivation