www.earnperhit.com/essay => Professional academic writing www.Lucky-Bet.site => Bet on Sports - 50% Deposit Bonus www.Lucky-Bet.site/casino => Online Casino - 5000$ Welcome Bonus www.Lucky-Bet.site/lotto247 => Lotto247 - Win Big, Live Free www.Lucky-Bet.site/eurobet => Best European Bookmaker RIT 101 Gage Kingsbury & Steve Wise, Senior Resource Fellows, NWEA Fusion 2012, the NWEA summer conference in Portland, Oregon It’s easy to say that the RIT scale is an equal-interval scale, but not as easy to back it up. This session will provide a conceptual review of the RIT scale and its characteristics and help to answer these questions: What is a RIT? What is a Rasch model? Why isn’t the number of correct answers used as the score? How are scores compared if students take different test items? Does a 200 RIT score from a third-grader mean the same thing as a 200 from an eighth grader? Learning outcome: - Gain a deeper understanding of the Rasch model. Audience: - New data user - Experienced data user - Advanced data user - District leadership - Curriculum and Instruction

1. RIT 101: Understanding
Scores from MAP
Steven L. Wise
Senior Research Fellow

2. RIT 101
• Unique features of the RIT scales
• Calibrating items for MAP
• The RIT scale and adaptive testing
• Scoring a test
• Interpretation of scores
2

3. Unique Features of RIT Scales
• Equal Interval
• Cross Graded
• Stable over time
• Allows us to assess change (growth) over time
• Allows us to develop item banks
• Allows us to give tests specific to student
needs
3

4. How do we use the RIT scale?
• The RIT scale is the platform upon which both
new items are calibrated, a test is chosen for a
student and a student’s score is computed and
interpreted.
• MAP is a computerized adaptive test (CAT),
which means that each student receives a test
that is tailored to his/her level of proficiency.
4

5. Item Calibration
• Item calibration is the process by which we
figure out how difficult an item is.
• This is extremely useful in both building an
item bank and administering a CAT
• Based on item response theory—specifically,
the Rasch model.
– Specifies the relationship between a student’s
proficiency level and his/her chances of passing
the item.
5

6. How do we decide a new
item’s difficulty?
• Some items are more difficult than others.
• We figure out an item’s difficulty by field
testing it during live test events.
• We then consider how many students got the
item right relative to their standing on the RIT
scale.
6

7. A Basic Math Item: 5 + 5 = ?
1.0
0.9
ProportionCorrect
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
120 170 220 270
RIT
7

8. Fitting a Rasch Curve
1.0
0.9
ProportionCorrect
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
120 170 220 270
RIT
8

9. Item Difficulty: the RIT value at which we
expect half of the students to pass the item.
1.0
0.9
ProportionCorrect
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
120 170 220 270
RIT
Difficulty = 170
9

10. The Item Bank
• Once an item has been calibrated, it (along
with its difficulty) will be added to the MAP
item bank.
• MAP banks contain thousands of test items.
• Large item banks are essential for using CAT.
10

11. Scoring a Test
• The scoring of a student’s test under the Rasch
model takes into account two things:
– how difficult the items were the student received
– how she did on those items
• A standard method of scoring is called “maximum
likelihood”
– This just means, “What is the most likely RIT score for a
student who performed as she did on the items she
received?”
• Conceptually, this is not as complicated as it sounds.
11

12. A One-item Test
1
0.9
0.8
0.7
Proportion Correct
0.6
0.5
0.4
0.3
0.2
0.1
0
130 140 150 160 170 180 190 200 210 220 230 240 250 260 270
RIT
If this item was passed, what are the most likely values of the student’s RIT?
What are the least likely values? 12

13. A Two-item Test
1
0.9
0.8
0.7
Proportion Correct
0.6
0.5
0.4
0.3
0.2
0.1
0
130 140 150 160 170 180 190 200 210 220 230 240 250 260 270
RIT
What if the Blue item was passed and the Red Item was failed? 13

14. A Three-item Test
1
0.9
0.8
0.7
Proportion Correct
0.6
0.5
0.4
0.3
0.2
0.1
0
130 140 150 160 170 180 190 200 210 220 230 240 250 260 270
RIT
What if the Blue and Green items were passed and the Red Item was failed?
14

15. Maximum Likelihood Scoring
and CAT
• Notice that item difficulty and student scores
are on the same scale (RIT).
• The best measurement occurs when students
are given items whose difficulties are well
matched to their proficiency levels.
• This is what a CAT does. It tailors the test to
each student by adjusting item difficulty.
• Result: all students can be measured with
equal precision.
15

16. How a CAT Works
1. Pick an item of appropriate starting difficulty.
2. The item is presented & answered by the
student.
3. If answer is right, choose a harder item to give
next. If answer is wrong, choose an easier item
to give next.
4. Repeat steps 2 & 3 until enough items have
been given.
5. Calculate the student’s RIT score.
16

17. Interpreting a RIT Score
• How is a student’s RIT score interpreted?
• A RIT score in math of, say 221, by itself is not
interpretable.
• We need to have one or more reference
points to interpret a score.
17

18. Reference Points for a Spring
RIT Score of 221 in Math
• Normative: Shauna’s 221 is at the 62nd percentile
relative to other 5th grade students.
• Growth: She has gained 13 RIT points since fall MAP
testing. Typical growth for students starting at the
same level was 9 points.
• Predictive: Her score indicates that she is on track to
being college ready by the 12th grade.
• Content: DesCartes provides information about
which skills Shauna is currently ready to learn.
18

19. Thank you for
your attention.
steve.wise@nwea.org