Reliability and Validity in Testing - PowerPoint PPT Presentation

Loading...

PPT – Reliability and Validity in Testing PowerPoint presentation | free to download - id: 6f8700-NGNlN



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Reliability and Validity in Testing

Description:

Reliability and Validity in Testing What is Reliability? Consistency Accuracy There is a value related to reliability that ranges from -1 to 1. – PowerPoint PPT presentation

Number of Views:61
Avg rating:3.0/5.0
Slides: 12
Provided by: edum98
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Reliability and Validity in Testing


1
Reliability and Validity in Testing
2
What is Reliability?
  • Consistency
  • Accuracy
  • There is a value related to reliability that
    ranges from -1 to 1.

3
Types of Reliability
  • Test-retest
  • Parallel/Equivalent forms
  • Inter-rater
  • Intra rater
  • Split half (Internal consistency)

4
Accuracy and Error
  • Every measurement has an error
  • Error can work either for you or against you.
  • Obtained score True score /- Error
  • Or True score Obtained score /- Error

5
Standard Error of Measurement
  • SD v1 r
  • SD Standard deviation
  • 1 is a constant
  • r Reliability value
  • What happens if SD 0?
  • What happens if r 1?

6
Using the SEM
  • To find the True score
  • True score Obtained score /- Error
  • As SEM is a standardised measure (much like
    standard deviation), can use the normal curve
  • Normal curve helps us to become more precise

7
What is our True Score?
  • How precise do we want to be?
  • Example SEM 4.5
  • Raw score 42
  • True score 42 /- 4.5 37.5 to 46.5
  • This is at 1 SEM
  • Using the Normal curve, we can be 68 sure that
    our score is between 37.5 and 46.5
  • If we want to be 92 sure, we use 2 SEM and the
    range will be between 33 to 51 (i.e. add another
    4.5)
  • What would the range be if we wanted to be 100
    sure?

8
Validity
  • What is test validity?
  • Does the test measure what it claims to measure
  • Usually determined logically and through
    reasoning, not with a value

9
Types of validity
  • Face validity
  • Construct validity
  • Concurrent validity
  • Predictive validity
  • Content validity

10
Issues with Validity
  • Types of validity often independent of each other
  • Other types of validity exists or can be created
  • Validity is often a matter of degree, not whether
    the test is valid or not valid.

11
Validity and Reliability
  • Does one require the other?
  • Can a test be valid but not reliable?
  • Can a test be reliable but not valid?
  • How does one affect the other?
  • Which is more important reliability or
    validity?
  • Practicality another concern and how it affects
    validity/reliability
About PowerShow.com