collier

• ex. you can use a measurement of your cake-baking skill as an operational definition of you intelligence. clearly this is not so. 
• This definition lacks reliability and validity

whether something looks valid on the surface

• Really Very Nasty
• R= Reliability
• V= Validity
• N= Norms

gives you a reference point

establishes that our measurement measures what its supposed to measure

• establishes that our measurement is stable or consistent (reliable)
• the correlation betwee two measurements of the same thing
• 1 means perfect reliability
• we want them to be high .6-.8

turns our abstract contruct into something we can measure

the thing that we are really interested in but we cant measure it directly

• each person answers questions in a variety of ways. if you only ask one quesrion, you might not get a true picture of that person.
• each item test what you want it to and plus some other nonsense
• when you average them the nonsense gets averaged out leaving only the construct of interest. 

• intrarater reliability: test the same person more than once
• interrater reliability: test different people

• retest the person on different occasions
• problems: memory effects and practice effects
• internal consistency: this is coceptually different, because we are not retesting in any way

• unidimensionality (single dimension) 
• only makes sense when all of the items are supposed to be measuring the same thing.

• aplit the test in hald, and correlate one half with the other half
• this is like treating one test as two
• it divides the test in half, which reduces the reliability
• problems: you could get many different scores, depending on how you split it

• correlate each item on the test with the total test score
• average them
• there is only one
• Alpha is the sign you will always see in reliabilty

like alpha but only applies to a test where there are right and wrong answers

an adjustment formula, to increase the reliability back to what it would be for the full-length test

• only applies when we expect people to agree with each other
• correlate the judges with each other
• ex. raters of videotapes
• doesnt apply to paper and pencil (objective) tests, but does apply where tests have subjective elements, such as projective tests