Classroom Assessment

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Classroom Assessment

• Ways to improve tests

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Improving Tests Judgmental Procedures

• Check your tests and items Do they
• adhere to item-writing guidelines?
• lead to score-based inferences?
• accurately reflect the content?
• provide representative coverage of all content
  and learning targets?
• provide fair and unbiased assessment?

3
Improving Tests Empirically Based Procedures

• Difficulty index (p)
• Number Getting Item Correct
• p
• Total Number of Examinees
• R
• T

4
Improving TestsEmpirically Based Procedures

• Item-Discrimination Index (D).
• D Correlation between an item and the total
  test score.
• Indicates the extent to which an item tends to be
  answered correctly by those who score high on the
  test.
• Can be positively discriminating or negatively
  discriminating, or non-discriminating.

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Empirically Based Procedures Discrimination
Index

• Type of Item Proportion Correct
• Positive Discriminator High gt Low
• Negative Discriminator High lt Low
• Non-discriminator High Low
• Popham gives instructions for for calculating and
  interpreting D on pages 244-247.

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Empirically Based Procedures Distracter
Analysis

• Particularly useful when an item needs revision.
• Item No. xx Alternatives
• (p .4, D -.5) A B C D O
• Upper 15 students 3 7 2 2 0
• Lower 15 students 3 4 4 3 1
• Why did nearly half the upper 15 students select
  alternative B?

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Empirically Based Procedure for
Criterion-referenced Tests

• Two general approaches
• Use a pretest and a posttest.
• D p(Post) - p(Pre)
• Use two groups of students.
• One having received instruction.
• One having not received instruction.
• D p(Instructed) - p(Not-Instructed)

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End