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Todays Topic

• Interpretation of Standardized and
  Norm-Referenced Measures
• Reliability, validity, normal curve

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Announcements

• Turn in your last classroom-based assessment
  instrument NOW!
• The draft of your Terminology Treasure Hunt will
  be due in two weeks. Make sure to take good notes
  this week and next, as they will be helpful in
  completing your assignment.
• Bring copies of the resources for the Terminology
  Treasure Hunt from e-reserves with you to class
  next week.
• Today, and for the following 2 weeks, we will be
  working on concepts related to standardized
  tests. You will need to know this to successfully
  complete your diagnostic assessment description
  critique, (due on Nov 25th). Dont delay in
  getting started!

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Quick questions or quandaries?
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Individual Activity

• Individually, come up with at least three
  sentences using the word reliable and at least
  three sentences using the word valid.
• These sentences do not have to have anything to
  do with assessment or evaluation -- they can be
  the kinds of things you would say in real life.

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Definitions
Reliability  1) Reliability refers to the
results obtained with an assessment instrument
and not to the instrument itself. 2) An
estimate of reliability always refers to a
particular type of consistency (i.e. over time,
inter-rater reliability, with different tasks).
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Definitions, cont.
Reliability   3) Reliability is a necessary but
not sufficient condition for validity. 4)
Reliability is primarily statistical.
(Linn Gronlund, 2000, pp. 108-109)
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Definitions, cont.
Validity  1.) Validity refers to the
appropriateness of the interpretation of the
results of an assessment procedure for a given
group of individuals, not to the procedure
itself. 2.) Validity is a matter of degree it
does not exist on an all-or-none basis.
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Definitions, cont.
Validity  3.) Validity is always specific to
some particular use or interpretation. No
assessment is valid for all purposes. 4.)
Validity is viewed as a unitary concept based on
various kinds of evidence.
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Definitions, cont.
Validity  5.) Validity involves an overall
evaluative judgment. It requires an evaluation
of the degree to which interpretations and use of
assessment results are justified by supporting
evidence and in terms of the consequences of
those interpretations and uses. (Linn
Gronlund, 2000, pp.75-76)
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Definitions, cont.
Validity is an evaluation of the adequacy and
appropriateness of the interpretations and use of
assessment results.   (Linn Gronlund, 2000,
p. 73)  
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Cautions related to use of validity
"Validity refers to the appropriateness of the
interpretation of the results of an assessment
procedure for a given group of individuals, not
to the procedure itself." "Validity is a matter
of degree it does not exist on an all-or-none
basis."  
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Cautions, cont.
"Validity is always specific to some particular
use or interpretation. No assessment is valid for
all purposes." "Validity is a unitary concept."
"Validity involves an overall evaluative
judgment." (Linn Gronlund, 2000, pp. 75-76)
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3 minute think-pair-share

• What have you learned reliability and validity?
• Anything new or interesting?
• Anything puzzling?

Take notes!
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Main Points
1) A test must be reliable for the interpretation
to be valid. 2) Reliability, in and of itself, is
not enough -- the interpretation must also be
valid for the individual and specified purpose of
assessment. 3) Validity refers to the
interpretation of the test results, not to the
test.
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Main Points, cont.
4) As a special educator, the most important
thing you need to learn about standardized tests
is how to interpret assessment results -- are
they valid FOR THIS CHILD AT THIS TIME?
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What does this mean for your diagnostic test
critique?
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10 minute break
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Tonights Terminology

• Reliability
• Validity
• Chronological age
• Raw age
• Norm-referenced (quick review)
• Normal curve

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Norm-referenced Tests

• Describe performance in terms of the relative
  position held in some known group (e.g., typed
  better than 90 percent of the class members).
• (Linn Gronlund, 2000, p. 42)
• NR assessments compare individual performance
  against others performance.

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What is a Normal Distribution?

• It is the idea that for a number of human
  characteristics, such as height or weight, most
  of the cases will cluster around the middle,
  with fewer at the high and low ends. So, if you
  plot the number of cases at each possible data
  point, you end up with the
  bell curve.

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Ways to talk about the middle(measures of
central tendency)

• Mean the statistical average
• Median the score where half fall above and half
  fall below.
• Mode the most frequent score

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In a normal distribution, the mean, median, and
mode are exactly the same.
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Write your height in inches on the provided
index card and give to Julia.
Are we "normal"?
Note 5 feet 60 inches
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Why is a normal curve important?

• Norm-referenced assessments are based on the
  assumption that human abilities, like height and
  shoe size, are normally distributed.
• A normal distribution allows us to calculate a
  number of important statistics, which allow us to
  compare an individuals score with that of their
  norm group.

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Testing terminology related to the normal curve

• Measures of Variability
• Range
• Standard deviation
• Standard score
• Z-score
• Deviation IQ
• Stanine
• Percentile rank
• Age equivalency
• Grade equivalency

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Looking ahead

• Standard deviation and standard scores

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Please take a minute for the minute paper