Presentation on theme: " A Test Must Be: ◦ Reliable ◦ Valid ◦ _____________________ = consistent ◦ _____ = measuring what it is suppose to measure."— Presentation transcript:
A Test Must Be: ◦ Reliable ◦ Valid ◦ _____________________ = consistent ◦ _____ = measuring what it is suppose to measure
Reliability Validity Construct Criterion Content Interrater Face
Reliability and Validity Reliable but not valid
Reliability and Validity Neither reliable nor valid
Reliability and Validity Reliable and valid
reliability = refers to test's consistency A reliable test minimizes error and provides repeatable consistent results
1) low precision ◦ characteristics of the instrument used 2) state of the participants ◦ depressed, moody, irritable 3) state of the experimenter ◦ depressed, moody, irritable… 4) state of environment ◦ noise, heat, etc.
Scan a multitude of information and decide what is important Manage time effectively 2Manage resources effectively. 3Scan a multitude of information and decide what is important. 4Decide how to manage multiple tasks. 5Organize the work when directions are not specific. 1Manage time effectively Rating Sheet Observedscore = Trueability + Randomerror Te+
Correlations used Normally ranges from -1.0 to Reliability coefficient is: __________________
Test-retest Alternate Forms Internal Consistency Inter-rater
Coefficient of stability is the correlation of the two sets of test scores.
Two versions of the same test with similar content Forms must be equal
Split half KR-20 Cronbach’s alpha
Measures scorer reliability Do the judges agree?
Scores by two independent judges and the scores are correlated _________________________
research clinical settings
Reliability Validity Test-Retest IC Alternative Construct Criterion Content Convergent Discriminant Factorial Interrater Face
Neither Reliable or Valid Highly Reliable but Not Valid Highly Reliable and Valid
Life and Death a Serial Killer (Broomfield & Churchill, 2002) Case Study…
Jan 9, 1991 – arrested in Florida paranoid, borderline personality disorder admits that she lied on the stand about self defense did it to “come clean” killed because of robbery and to eliminate a witness plan murders, selected the men “there was no self-defense”
“the world is full of evil” made a day as prostitute met Tyra in bar, lesbian relationship Tyra made a state’s witness Tyra not charged in the murders participated with police sorry about her actions
“doing lying biz to beat the system” her report of Richard Mallory was convincing Mallory spent 5 years in jail for sex crimes “you have to kill Aileen Wournos because she will kill again” talked about conspiracies in early 1990s tended to sabotage own defense
oral sex for cigarettes at age of 9 incestuous relationship with brother Keith Aileen’s grandfather beat her with black belt rumored that he was her biological father Biological mother abandoned her at 6 months “father” sent to jail for sodomizing a boy later he committed suicide
Had baby boy at age 13 two years living in the woods survived by hooking treated poorly by neighbourhood kids father of Aileen’s child was the local pedophile
Left Michigan at age 16 Doing drugs at time (LSD) know for violent temper knocked a man out with beer bottle and another with billiard ball
Married Lewis Fell age 76 restraining charges, beat Lewis with walking stick starting dating women in late 20s Tyra described Aileen as –fantasist, jealous and possessive who could be violent and frightening had fantasies of being raped
believed police had known about the first murder but allowed her to continue mind is being controlled by radio waves, poisoned food, threatened of rape while in prison
I am so burning f..in mad about how I am being… I’ve got to wait for my execution I want to get in the f..ing chamber tomorrow and leave And then they play, since I waived off I have nothing but Psychological and physical f… problems, playin with it because I am on hold with my execution. I’m so f..in mad I can’t see straight And they’re just daring me to kill again They got me pissed…United States Supreme court you f…in I’m telling you man, you motherf…. Keep f..ing with my goddamn execution and there’s going to be blood shed. I’m sick of this, get that f..ing warrant signed.
using “sonic pressure” on my head since 1997 ◦ (this was stated on Oct 8th, 2002). Believes had eye in cell, believes that the tv or mirrors were rigged. Crushing my head, using sonic pressure. Believes that police had surveillance, before she killed. It was the cops that made her do it.
Advantage Establish causality X causes change in Y Disadvantage May be artificial
How would you establish this? You need at least 2 groups ◦ Control ◦ Experimental
IQ tested before intervention This group receives a placebo IQ tested after receiving placebo
IQ test prior to administering drug This group then gets the drug IQ tested again
AAre there differences before testing? if yes, sample may not be random AAre there differences after testing?
summarized by letter r ranges between -1 and + 1 ◦ Under ideal conditions closer to -1 or +1, the stronger the r
X variable might cause the Y variable. Y variable might cause the X variable. Another variable influences both X and Y. Strong correlation by chance.
Little Albert (Watson) Obedience (Milgram) Stanford Prison Study (Zimbardo)
ethics are standards regarding the treatment of others these standards apply to both research and clinical practice many disciplines have ethical codes CPA (Canadian Psychological Association) APA (American Psychological Association)