Download
1 / 12
120 likes | 125 Views
Validity and Reliability II: The Basics EDU 300 | Newberry College Jennifer Morrison. Validity and Reliability II. What is the difference between reliability and validity? Why are they important concepts? How can you make your assessments more reliable?
E N D
Validity and Reliability II:The Basics EDU 300 | Newberry College Jennifer Morrison
Validity and Reliability II • What is the difference between reliability and validity? Why are they important concepts? • How can you make your assessments more reliable? • How can you make your inferences from those assessments more valid?
Reliability Definition #1 Statisticians say an assessment is reliable when it gets consistent results over time. That means if Susie takes Assessment X in January she will get the same results when she takes the assessment (even if it’s a different version) in June, given that she does not learn anything that’s on Assessment X between tests.
Reliability Definition #2 For our purposes, let’s use James Popham’s definition of reliability – that the assessment measures what it is supposed to measure. That means when Susie takes Assessment X that it actually assesses what Susie learned in Course X. Do your assessments measure what they are supposed to measure? How do you know?
There is a general feeling that data from teachers’ classroom tests are not reliable. Why?
On Target vs. On Topic For classroom assessments to be reliable in regard to state standards, assessment items must be on target, not just on topic.
Example Standard = Use context clues to determine the meaning of technical terms and other unfamiliar words. (SC E4-3.1) Something used to confine a dog is… A) a cage, B) training, or C) identity tags. How would the assessment question have to be structured in order to assess the standard effectively? How would the assessment question have to be structured in order to assess the standard at an advanced level?
SEM • A standard error of measurement is a statistical number that indicates the amount of error to allow for when interpreting assessment scores. The SEM shows how many points we must add to or subtract from an individual’s test score in order to estimate the range of that individual’s true score, or score free from error. • We use the SEM to create a score band or confidence band.
Validity • Are the inferences we make from the data accurate? • We are most likely to draw valid inferences when we know… • the assessment and assessment procedure. • how the assessment results were determined and what they mean. • what was assessed. • the consequences of using the assessment.
