Lecture 8b: interpreting the WAIS IV

[@atticbrowser9698]

Thank you for a very clear and helpful lecture. I really appreciate you taking the trouble to share these more widely via KZbin.

[@keithdonohue4631]

You're welcome

[@ZorbaPress]

Keith, thank you very much. These lectures are so valuable, and interesting, too. Thanks for sharing them with the KZbin world.

[@golddude6069]

You should put a timestamp for different section of your video :)

[@patricklumbroso1369]

Well done KD. Very dry topic, yet very well explained. A rare and valuable find.

[@keithdonohue4631]

Thanks!

[@No-ky3kb]

Thanks for posting this for everyone to access Keith you da man

[@keithdonohue4631]

You’re welcome!

[@angelDanJonathan]

When calculating sum of scaled scores do you take the index of strength of the test taker for all indexes? I understand that only one subtest substitution per index is acceptable. For example strengths in Block Design (16) and Matrix (16) Reasoning but weakness in Figure Weights (14) thus out of curiosity we used the supplemental subtest of Picture Completion (15) to complete calcuation (sum for this index is 47). Would this work? If it depends then in this case the test taker only wants to know what their intelligence so would sum of index strengths work here?

[@anketemmerman34]

Thanks, very informative presentation! Just wondering: when do you choose overall or personal ability level when performing the index discrepancy analysis?

[@keithdonohue4631]

Hmmm...it's been a while since I taught this class or administered a WAIS, but if I remember correctly, discrepancy analyses involve comparisons between different index scores, such as Verbal Comprehension or Perceptual Reasoning. These analyses use information about the overall population to interpret differences. For example, you might want to know whether a particular observed difference is statistically significant [how likely is it for such a difference (or one bigger than it) to occur in a population of differences that is centered over zero (i.e., the "true" difference is zero)]. You might also want to know how frequently such a difference is observed in the general population [fairly often (then it might not be all that interesting) or fairly rarely (then it might be interesting)]. These questions are different than the types of questions that you are asking when you do strengths and weaknesses analyses. For strengths and weakness analyses, you want to know whether a particular subtest [or really, the mental abilities that underlie the test] is a strength or a weakness for that particular test-taker. In order to answer this question, you can compare scores on individual tests to either an average of all the tests or an average of just the three tests that make up Verbal Comprehension or Perceptual Reasoning. Your decision about using either the overall average [for that particular test-taker] or an average for just Verbal Comprehension or Perceptual Reasoning depends on how much variability there is in the scores for the subtest. If there isn't a lot of variability, then an overall average makes the most sense. If there is a lot of variability [especially if your discrepancy analysis suggested significant difference between Verbal Comprehension and Perceptual Reasoning"], then using an average for just Verbal Comprehension or Perceptual Reasoning make more sense. Does this answer your question?

[@anketemmerman34]

​@@keithdonohue4631 Thank you, Keith, for your precious time to answer my question. Much appreciated. I totally follow your explanation. I understand the whole reasoning behind overall average or VCI/PRI average for the strengths and weakness analyses. However, I still don't quite understand when to choose the personal average when it comes to index score discrepancy analysis (for instance VCI vs PRI). Maybe in case of large internal inconsistency in an index? Thanks in advance.

[@uah9031]

Where is lecture 8a?

[@keithdonohue4631]

I think that the numbering of my lectures is a little bit inconsistent, because it is based on a course that I used to teach live. I made a practice of re-recording some of the lectures, if students wanted them, or if I felt they might need a resource for review. Sorry for the confusion.

[@ariannagonzalez6651]

Thank you for sharing your lecture.

[@keithdonohue4631]

You're welcome.

[@omdthe9382]

This video is fantastic. Thnx

[@keithdonohue4631]

You're welcome.

[@MsPocahontasbeauty]

How do you determine whether or not to use 90% or 95% Confidence Intervals?

[@keithdonohue4631]

I suppose it depends on the confidence that you want to have in your estimate. If you want to feel more confident that your interval (probably -- i.e., 95 times out of 100) captures the true score for the test-taker, use the wider 95% interval.

[@MsPocahontasbeauty]

Keith Donohue Thank you!

[@MsPocahontasbeauty]

Keith Donohue I am stuck on another concept. How do you determine strength or weakness?

[@keithdonohue4631]

@@MsPocahontasbeauty I cover this in the video, at about the one hour mark, when I start to talk about analyses on the subtest level

[@nederlandseveganist3028]

Does the digit span only go up to 9 forward and 8 backward?

[@LamatoroMD]

Muchas gracias por este tremendo aporte.

[@keithdonohue4631]

You're welcome!

[@johnkesslerbonayon559]

May I ask why scattered data in scaled scores is difficult to interpret?

[@keithdonohue4631]

Hmm... It's been a while since I taught my assessment class or even used a WAIS, but let's see if I can answer your very good question. We can think of the WAIS (and many tests of cognitive abilities) like a set of bigger scores, made up of smaller scores. The FSIQ and GAI scores are made up of composite index scores (like VCI, PRI, etc.). And the composite index scores are made up of subtest scores. All these scores are trying to tell you something about the test-takers abilities. The FSIQ score is trying to tell you their overall cognitive abilities, the VCI score is trying to tell you their verbal comprehension ability, the vocabulary subtest score is trying to tell you their ability to use vocabulary... If all the components that make up a particular score are very consistent, then we can usually feel confident that the score is giving us good information about that test-taker's actual or "real" abilities. If all the composite index scores that make up the FSIQ are really high, then we might feel pretty confident in thinking that the test-takers overall cognitive ability is also really high. If some of the composite index scores are high, but others are low, the overall FSIQ score might still be fairly high, but we might now feel less confident that it is giving us good information about the test-takers overall cognitive ability (what the FSIQ score is supposed to be telling us) -- maybe that person really has varied cognitive abilities, such that they are stronger in some areas and weaker in others....?

[@keithdonohue4631]

In a sense, this is all just classical test theory. Any observed test score (FSIQ, VCI, vocabulary subtest) is made of of the test-takers "true" score (a perfectly accurate measure of their ability in that area) and error (all the things that cloud or distort our understanding of that true score). Error is operationalized as variability in measurement. If the test-takers scores on a given composite area are highly variable, that is a lot of error in our measurement of whatever the index for that composite area is supposed to be measuring. We should feel less confident that we know what the test-taker's score should "really" be.

[@ssss6257]

Where is lecture 8a

[@keithdonohue4631]

I think that there isn't a lecture 8a. It's been quite a few years since I last taught this course (I'm in full-time practice, now), but I remember that the numbering got a little bit off, because I was mixing online work with in-class work. I'm pretty sure that this lecture is just supposed to follow the one on introduction to ability testing (even though the numbering doesn't make complete sense!).

[@ssss6257]

@@keithdonohue4631 Thank you for helping out. I had a quiz tomorrow and i needed an integrative report. I thought that the 8a lecture might have anything on that. You saved a lot of my time today. Thank you again.

[@acidrock202]

Hi keith I saw youre video. would you be able to input two tests I have into the report writer program you have?

[@keithdonohue4631]

Hello Nathan. I am sorry, but I don't have access to the scoring program that Pearson offers, and I don't have the time to score and interpret tests by hand.

[@tomhsu0420]

Oh my God, Sir, you go hard!!

[@farahizzati9193]

may i know if i would like to do the WAIS test with my classmates, what tools do i need. So i only need to get the WISC-IV Administration and Scoring Manual to calculate our scores?

[@keithdonohue4631]

In order to administer the Wechsler Adult Intelligence Scale (WAIS) or the Wechsler Intelligence Scale for Children (WISC), you need a the testing kit for the test (i.e., the WAIS or the WISC). This kit contains the testing materials, forms, and manuals that you will need. However, both tests have a "level C" classification, which means that they should only be purchased and used by people who have at least a master's-level education in psychology, education, or a related field (including training in testing); appropriate licensing to administer psychological tests (depending on where you live); or supervision by a licensed professional. Basically, you really shouldn't just buy and administer the test -- even just for fun or educational purposes. Doing so can lead to confusing or hurtful outcomes for your classmates (e.g., then may mistakenly think that their intelligence is lower than it really is), and it can degrade the future usefulness of the test (e.g., you classmates will now have advanced knowledge of the test materials, so if they ever have to take the tests for real, they will have an advantage that will invalidate their test results).

[@farahizzati9193]

Could you suggest how should I measure cognitive performance. I realise WAIS includes verbal, memory, perception and processing speed hence I would like to use this as a method of measurement for a small size of 20-30 pax as it has a comprehensive subtests which is not too lengthly for my project which will last for another 5 months. Please advice. I am an undergrad but I do have 2 researcher and a Prof guiding and overlooking my interpretation of the cognitive performance measurement.

[@keithdonohue4631]

It might be helpful if you specified what aspect of cognitive performance (attention, working memory, processing speed, etc.) you are interested in. Since you have a relatively short amount of time to work with, you should probably consider a group-administered test of mental ability, such as the MAB-II. You could administer this type of test to a whole group of research participants, at once. In contrast, you would have to administer the WISC or WAIS to each participant, one-at-a-time, which requires a lot of time and advanced training.

[@farahizzati9193]

Keith Donohue The project is to correlate indoor air quality and cognitive performance hence I am tasked to focus and set up a list of tests to measure cognitive in different aspects. Then I will hand over no the next student to do the cross link to identify if there are significant impact of air particles and cognitive performance. The cognitive test should be tested on student aged 20-30. May I know if there are any other suitable test method I should look into instead of WAIS. Thank you for your recommendation on MAB-II I will look into it and find the manual.

[@keithdonohue4631]

It seems like your best bet is to use a group-administered test battery that is well-validated and has good norms for interpretation. You might want to consider the Wonderlic Personnel Test (WPT-R) or even the Raven's Progressive Matrices, which can be administered individually or in group-format. All of the test batteries that I have mentioned are professionally developed and published. This means that they can be a bit expensive to purchase, but the value that you get for the money is in the validation and norms, and also the technical support for interpretation. If you can't afford these types of tests, you might want to consider some of the common neuropsychological tests that I mention in one of my later lectures. Many of these (e.g., the COWAT) are available for free (?) on the internet. The problem is that it can be difficult to track down appropriate norms for interpreting them.

[@gayathriveliath]

Thankyou so much for this!!!

[@keithdonohue4631]

You're welcome. I'm always happy when I see that people have found my old psychology lectures. It has been a while since I last made a new one. I'm in clinical practice, now, so I don't have much time. But maybe someday I will add a new lecture or two. I'd like to do one on the new MMPI-3.

[@myplaywithwords]

Thank you.

[@TonyTheSamurai]

Muy Bueno!

[@keithdonohue4631]

Thanks!

[@robloxplay6579]

hbh

[@robloxplay6579]

ggg

[@golddude6069]

Lol *Buys WAIS then snitches on his seller*