PTA EXAM Whitey (Reliablity & Validity, Reasearch concepts, Sampling)

Realiablity

Reproducibility or repeatability of measurments.

Internal Consistency

The extend to which items or elements that contribute to a measurment reflect one basic phenomenon or dimension.

EX: In PT a functional assessment scale shoud only include items that relate to patients’ physical function

Alternate Forms Reliability

AKA as parallel forms reliability. It assesses the consistency or agreement of measurments obtined with different forms of a test. Is essential if different forms of test are used interchangeably.

EX: SAT, GRE, and NPTE can be administered each year as long as different versions of the tests are considered equivalent measures.

Intrarater Reliability

The consistency or equivalence of repeated measurements made by the same person over time.

Interrater Reliability

The consistency or equivalence of repeated measurements made by more than one person. Indicates agreement of measurments taken by different examiners.

Test-Retest Reliability

The consistency or equivalence of repeated measurements made on the same indvidual on seperate occasions. affected by interval between tests, effects of fatigue or learning, and changes in the characteristicc being measured.

Validity

Degree to which a useful or meaningful interpretation can be inferred from a measurment.

Face Validity

Degree to which a measurment appears to test what it is supposed to do. insufficient documentation of validity, it is an improtant form of validity because patients may not be compliant with reapeated testing if they don’t see how the measurments derived from the tests relate to their specific problem.

Content Validity

Degree to which a measurment elements of a construct and the items in a test adequately reflect the content domain of interest and not extraneous elements.

Construct Validity

Degree to which theoretical construct is measured by a test or measurment. Evidence of construct validity is through logical argument based on theoretical and research evidence.

Criterion-Related Validity

Validity of the measurment is established by comparing it to either a different measurment often considered to be a “gold standard” or data obtained by different forms of testing.

Concurrent Validity

Form of criterion-related validity in which an interpretation is justified by comparing a measurment to a “gold standard” measurment at approximately the same time.

Predictive Validity

Form of criterion-related validity in which the measurment is considered to be valid because it is predictive of a futrue behavior or event.

Prescriptive Validity

Form of criterion-related validity in which the measurment suggests the form of treatment the person should recive. The prescriptive validity of the measurment of asystole on ECG could be said to have prescriptive validity if patients with this arrhythmia are successfully revived by cardio pulmonary resuscitation techniques.

External Validity

The extent to which the results of an experiment can be generalized across population, times, and settings.

The validity of a measure referred to the:

Accuracy with which it measures the construct

Which statement is true regarding the relationship between validity and reliability?

A valid test must be reliable

Qualitative Data

AKA categorical data, represents different categories distinguished by a non-numeric characterisitc (e.g., eye color)

Quantitative Data

Data consisting of numbers that represents counts or measurments.

Systematic Review

A comprehensive review of the medical literature that uses explicit methods to systematically search, idendity, appraise, and summarize all literature on a specific issue.

Meta-Analysis

A systematic review that uses a statistical technique to derive an estimate of effect size by combining the results of several rendomized controlled trials to determine the overall effectiveness of a treatment.

Randomized Controlled Trail (RCT)

A form of experimental research used to assess the relative effect of a specific intervention compared to a control condition

Cohort Study

A type of longitudinal, observational study in which individuals with a risk factor or exposure are followed over time to compare the occurence of a disease in the exposed group to that of the group of unexposed individuals.

Case Control Study

A type of retrospective,observational study in which individuals who already have a particular disease are matched with a comparision group of individuals without the disease.

Cross-Secional Study

A type of observational study where the data or observations are made at only one point in time and all subjects are tested at relatively the same time.

Case Report or Case Series

In-depth description of an individual’s condition or response to treatment. Case reports may be used to generate theories and hypotheses for future research.

Nominal (AKA classification scale)

Values of the variable are mutually exclusive and exhaustive categories, so that each object or person can be assigned to only one category. Qualitative rather than quantitative.

EX: blood type, type of breath sound, type of arthritis

Ordinal (AKA ranking scale)

Data are ranked on the basis of property of the variable, but the intervals between the ranks may not be equal or known.

EX: MMT grades, levels of assistance, pain, joint laxity grades.

Interval

The intervals between adjacent values are equal, but there is no true zero point.

EX: Temp F or C scale, developmental and functional status tests.

Ratio

The intervals between adjacent values are equal and there is zero point.

EX: ROM, distance walked (m), time to complete an activity (S), and nerve conduction velocity (m/sec).

Levels of evidence (highest to lowest)

1. systematic reviews

2. cohort studies

3. case control studies

4. case series

5. opinion

T/F: The 25th percentile is known as the first quartile.

True

Which measure of center would be most valuable in defining quartiles in a data set?

Median

__ percent of all values fall above and below the mean, median, and mode in a normal distribution.

50

Median

A measure of central tendency

Hawthorne

Name of the effect describing a change of behavior in response to being obersved or studied

Descriptive research

Recording, analyzing, and interpreting conditions that exist for the purose of classfication and understanding a clinical phenomenon.

Exploratory Research

Examines the dimensions of a phenomenon of interest and its relationships to other factors

Range of motion documented in degrees is a form of which type of data?

Continuous

Which of the following refers to a result that is not due to chance?

Significant result

The measures of central tendency are

Mean, Median, Mode

What type of scale is used on the Berg Balance Scale?

Ordinal

What is the term for the approach to clinical decision making that integrates the best available evidence from research with clinical experience and patient preferences?

Evidence-based practice

Which measure of central tendency can be applied to nominal data?

Mode

Variables such as gender and nationality are measured on which scale?

Nominal

Population

Complete collection of elements to be studied. The group to which the results of research are intended to be generalized.

Sample

A subset of elements drawn from a population to draw conclusions or make estimates about the larger population.

Sampling Error

The chance difference between the statistic calculated from a sample and the true value of the parameter in the population. Sampling error is inherent in the use of sampling methods.

Probability Sampling

A method of sampling that uses some form of random selection.

Simple Random Sampling

Subjects have an equal chance of being selected for the sample

Systematic Sampling

Subjects are selected by taking every nth subject from the population.

Stratified Random Sampling (AKA proportional or quota random sampling)

Population is divided into homogenous subgroups (strata) and then a simple random sample is drawn from each.

Cluster Sampling

Population divided into clusters or areas and a random sample of clusters is selected.

Non-Probability Sampling

Any method of scampling that does not involve selection of subjects

Convenience Sampling

The sample is selected from subjects who are convenient or readily available to the researcher.

Purposive Sampling

Subjects are deliberatly selected based on predefined criteria chosen by the investigators

What type of sampling is utilized when subjects are selected by asking existing subjects to identify the names of other potential subjects?

snowball sampling

A sampling method in which each unit that is selected for the sample is put back into the population before the next unit is drawn from the sample is known as:

Sampling with replacement

A sampling method in which the population size decreases as the size of the sample increases is known as:

sampling without replacement

Systematic sampling and cluster sampling are examples of which type of sampling method used in human research? 

Probability sampling

Researchers investigating the effects of an intervention on an extremely rare genetic condition would most likely utilize which sampling method?

purposive sampling

Sampling by state is an example of which sampling method?

cluster sampling

Which of the following sampling methods is an example of non-probability sampling? 

quota sampling

Which sampling method would be the most desirable when a research study involves human subjects?

probability sampling without replacement