Download Standardized Tests

Standardized Tests!
Testing Controversies!
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If you lived in Scarsdale would you have been
protesting?!
Do we test too much?!
What did you think about what the woman
said about the tests driving the curriculum?!
Thought Questions!
What is the primary difference between
achievement and intelligence tests?!
n  There are different purposes for giving
achievement and intelligence tests. What
are they?!
n  What is the best description of
psychometric intelligence ?!
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Functions of Standardized Tests!
Student Assessment!
n  Diagnosis!
n  Placement and Selection!
n  Accountability!
n  Predictive Validity!
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What is a standardized test?!
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A test that has standard procedures for
administration, scoring, and
interpretation.!
Advantages of Standardized Tests!
Evaluating students general educational
development in the basic skills & in
learning outcomes common to many
courses of study!
n  Evaluating student progress during the
school year or over a period of years!
n  Determining strengths & weaknesses!
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Weaknesses of Standardized Tests!
Evaluating the learning outcomes and
content unique to a particular class or
school!
n  Evaluating students day-to-day progress!
n  Evaluating knowledge of current
developments in rapidly changing
content areas such as science and social
studies!
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Types of Achievement Tests!
State Developed Tests!
! !N.C. EOG s, FL FCAT s, VA s SOL s!
n  Publisher-Developed Norm-referenced batteries!
! !ITBS, CAT, GRE, Stanf. Ach. Test!
n  Publisher-Developed Norm-referenced content
area tests!
n  Publisher-Developed Criterion-referenced tests!
!
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No Child Left Behind
Will all students be at grade level by 2014?
Who did you identify with most in the video, anyone you
did not agree with?
How has NCLB affected you?
http://www.youtube.com/watch?v=hSTzLILQx3c
http://www.youtube.com/watch?
v=Ugeb_B3aJXM&feature=related
Some popular tests to be aware of:!
California Achievement Test (CAT)!
n  Iowa Tests of Basic Skills (ITBS)!
n  Metropolitan Achievement Tests (MAT)!
n  Stanford Achievement Tests!
n  TerraNova!
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Why do we use these?!
High technical quality!
n  Standard directions for administration
and scoring!
n  Norms based upon large national
samples!
n  Equivalent forms!
n  Comprehensive manuals!
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Using Achievement Tests:!
Be wary of using subtests for diagnostic
purposes unless enough items are
included!
n  What is a norm group and what is the
benefit of having a norm group?!
n  Norm groups provide a standard frame
of reference!
n  Equivalent forms!
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Judging the Adequacy of Norms!
Should be relevant (Who do you want to
compare your scores to?)!
n  Should be representative!
n  Should be up to date!
n  Should be comparable!
n  Should be adequately described!
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Achievement Batteries!
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Consists of a series of individual tests all
standardized on the same national
sample!
Some Aptitude/Intelligence tests "
to be aware of:!
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Wechsler Intelligence Tests (WISC, WAIS)!
Stanford-Binet!
Raven s Advanced Progressive Matrices!
Cognitive Abilities Test (CogAT)!
Graduate Record Examination (GRE)!
Otis-Lennon School Ability Test (OLSAT)!
Cattell Culture-Fair Intelligence Tests!
Armed Services Vocational Aptitude Battery
(ASVAB)!
Differential Aptitude Test (DAT)!
Questions about Aptitude &
Intelligence!
What is meant by aptitude? What are
aptitude tests measuring?!
n  How is IQ determined? - chart -!
n  Can IQ change over time?!
n  Who administers an individual
intelligence test?!
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Normal Curve!
34%
13.5%
34%
13.5%
2.5%
-3
2.5%
-2
Mean
+1
-1
Standard Deviations
+2
+3
Aptitude Tests!
Do not measure fixed capacity but rather
a different type of ability used to predict
future performance!
n  Common distinction: achievement tests
measure what a student has learned and
that aptitude tests measure the ability to
learn new tasks!
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Why use aptitude tests when
you have achievement tests?!
Can be administered in a relatively short
time!
n  Can be used with students of more
widely varying educational backgrounds!
n  Can be used before any training or
instruction!
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Bell Curve for Wechsler Intelligence Test
Specific theories of importance:!
Spearman vs. Thurstone!
n  Guilford s 120 abilities!
n  Crystallized & Fluid intelligence!
n  Gardner s multiple intelligences!
n  Others include David Perkins & Robert
Sternberg!
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What is general intelligence?!
General ability typically measured via
standardized tests--symbolized as g!
n  Predictive power strongest when
facing novel tasks or beginning
competence!
n  Considered to be reasoning ability
(typically inductive) that is highly
dependent upon working memory-making transformations in your head!
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General intelligence, or g, reflected by the
positive manifold between tests of cognitive
ability
Suppose we measured the right foot length of 30 teachers
and graphed the results.
Assume the first person had a 10 inch foot. We could create
a bar graph and plot that person on the graph.
Number of People with
that Shoe Size
If our second subject had a 9 inch foot, we would add her to
the graph.
As we continued to plot foot lengths, a
8
pattern would begin to emerge.
7
6
5
4
3
2
1
4
5
6
7
8
9 10 11 12 13 14
Length of Right Foot
Number of People with
that Shoe Size
Notice how there are more people (n=6) with a 10 inch right foot
than any other length. Notice also how as the length becomes
larger or smaller, there are fewer and fewer people with that
measurement. This is a characteristic of many variables that we
measure. There is a tendency to have most measurements in
the middle, and fewer as we approach the high and low
extremes.
If we were to connect the top of each bar, we
8
would create a frequency polygon.
7
6
5
4
3
2
1
4
5
6
7
8
9 10 11 12 13 14
Length of Right Foot
Number of People with
that Shoe Size
You will notice that if we smooth the lines, our data almost
creates a bell shaped curve.
8
7
6
5
4
3
2
1
4
5
6
7
8
9 10 11 12 13 14
Length of Right Foot
You will notice that if we smooth the lines, our data almost
creates a bell shaped curve.
Number of People with
that Shoe Size
This bell shaped curve is known as the Bell Curve or the
Normal Curve.
8
7
6
5
4
3
2
1
4
5
6
7
8
9 10 11 12 13 14
Length of Right Foot
Number of Students
Whenever you see a normal curve, you should imagine the
bar graph within it.
9
8
7
6
5
4
3
2
1
12 13 14
15 16 17 18 19 20 21 22
Points on a Quiz
The
Nowmean,
lets look
mode,
at quiz
andscores
median
forwill
51all
students.
fall on the same
value in a normal distribution.
12
13 13
12+13+13+14+14+14+14+15+15+15+15+15+15+16+16+16+16+16+16+16+16+
17+17+17+17+17+17+17+17+17+18+18+18+18+18+18+18+18+19+19+19+19+
14 14 14 14
19+ 19+20+20+20+20+ 21+21+22 = 867
15 15 15 15 15 15
12, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 22
16 16 16 16 16 16 16 16
867 / 51 = 17
17 17 17 17 17 17 17 17 17
18 18 18 18 18 18 18 18
19 19 19 19 19 19
Number of Students
20 20 20 20
21 21
9
8
7
6
5
4
3
2
1
22
12 13 14
15 16 17 18 19 20 21 22
Points on a Quiz
Normal distributions (bell
shaped) are a family of
distributions that have the
same general shape. They
are symmetric (the left side is
an exact mirror of the right
side) with scores more
concentrated in the middle
than in the tails. Examples of
normal distributions are
shown to the right. Notice
that they differ in how spread
out they are. The area under
each curve is the same.
If your data fits a normal distribution, approximately 68% of
your subjects will fall within one standard deviation of the
mean.
Approximately 95% of your subjects will fall within two
standard deviations of the mean.
Over 99% of your subjects will fall within three standard
deviations of the mean.
The mean and standard deviation are useful ways to describe a set of
scores. If the scores are grouped closely together, they will have a smaller
standard deviation than if they are spread farther apart.
Small Standard Deviation
Same Means
Different Standard Deviations
Large Standard Deviation
Different Means
Same Standard Deviations
Different Means
Different Standard Deviations
When you have a subject s raw score, you can use the mean
and standard deviation to calculate his or her standardized
score if the distribution of scores is normal. Standardized
scores are useful when comparing a student s performance
across different tests, or when comparing students with each
other.
z-score
-3
-2
-1
0
1
2
3
T-score
20
30
40
50
60
70
80
IQ-score
65
70
85
100
115
130
145
200
300
400
500
600
700
800
SAT-score
The number of points that one standard deviation equals
varies from distribution to distribution. On one math test, a
standard deviation may be 7 points. If the mean were 45, then
we would know that 68% of the students scored from 38 to 52.
24 
31
38
On another test, a
standard deviation may
equal 5 points. If the mean
were 45, then 68% of the
students would score from
40 to 50 points.
45
52
59
Points on Math Test
30
35
63
40
45
50
55
Points on a Different Test
60
Data do not always form a normal distribution. When most of
the scores are high, the distributions is not normal, but
negatively (left) skewed.
Skew refers to the tail of the distribution.
Number of People with
that Shoe Size
Because the tail is on the negative (left) side of the graph, the
distribution has a negative (left) skew.
8
7
6
5
4
3
2
1
4
5
6
7
8
9 10 11 12 13 14
Length of Right Foot
When most of the scores are low, the distributions is not
normal, but positively (right) skewed.
Number of People with
that Shoe Size
Because the tail is on the positive (right) side of the graph,
the distribution has a positive (right) skew.
8
7
6
5
4
3
2
1
4
5
6
7
8
9 10 11 12 13 14
Length of Right Foot
When data are skewed, they do not possess the
characteristics of the normal curve (distribution). For
example, 68% of the subjects do not fall within one
standard deviation above or below the mean. The
mean, mode, and median do not fall on the same score.
The mode will still be represented by the highest point
of the distribution, but the mean will be toward the side
with the tail and the median will fall between the mode
and mean.
Negative or Left Skew Distribution
Positive or Right Skew Distribution
Normal Distribution (Bell Curve) with
Wechsler Intelligence Test Scores
Questions about Grade
Equivalent Scores!
What does it mean if a 4th grader has a
grade equivalent score of 7.3?!
n  What is the purpose of grade equivalent
scores?!
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Avoid Misconceptions with Grade
Equivalent Scores!
Don t confuse norms with standards of
what should be!
n  Don t interpret a grade equivalent as an
estimate of the grade where a student
should be placed!
n  Don t expect that all students should
gain 1.0 grade equivalent each year!
n  Don t assume that the units are equal at
different parts of the scale!
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Avoid Misconceptions with Grade
Equivalent Scores!
Don t assume that scores on different
tests are comparable!
n  Don t interpret extreme scores as
dependable estimates of student
performance level!
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Some Popular Standard Scores!
Mean!
SD!
Scale Name!
500!
100!
GRE; SAT; GMAT!
100!
15!
Wechsler IQ!
20!
5!
ACT!
50!
10!
T-scale MMPI!
Standard Scores!
A calculated score that enables a
researcher to compare scores from
different scales!
n  Z-score most popular (mean of zero and
SD of one)!
n  z = (X-M)/SD!
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T Scores!
Another type of standard score -sometimes preferred because all
numbers are positive!
n  T score = 50 + 10(z)!
n  Example: If you scored 2 SD s above the
mean on a reading test your T score
would be 50 + 10(2) = 70!
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Stanines!
Another type of standard score -preferred for interpretability!
n  Score between 1 and 9 with each stanine
covering 1/2 standard deviation unit (e.g.,
stanine of 5 = 40%ile-59%ile)!
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A Graphic Explanation of Stanines!
Problem Solving:!
You scored 107 on the WISC. What
percent of people scored above you?!
n  What percent of people score between
100 and 125 on IQ tests?!
n  What percent of people score below 60
and above 130 on the WISC?!
n  A score of 91 on the WISC would place
you in front of what percent of people?!
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http://www.webster.edu/~woolflm/zscores.html