Item Discrimination: A Guide to Identifying Effective Test Items

Question 1

Which formula is used to calculate item discrimination?

Accepted Answer

Item Discrimination = (Mean of the Upper Group - Mean of the Lower Group) / Standard Deviation of the Upper Group

Answer

Item Discrimination = (Mean of the Upper Group - Mean of the Lower Group) / Standard Deviation of the Lower Group

Answer

Item Discrimination = (Mean of All Test Takers) / Standard Deviation of the Test

Answer

Item Discrimination = Squared Error of the Upper Group - Squared Error of the Lower Group / Variance of the Test

Question 2

What is the main purpose of conducting item discrimination analysis?

Accepted Answer

To identify items that effectively differentiate between high-performing and low-performing test takers

Answer

To detect items that are difficult for all test takers

Answer

To detect items that are easy for all test takers

Answer

To detect items that are biased against particular subgroups of test takers

Question 3

What statistical method is employed to calculate item discrimination?

Accepted Answer

Point-biserial correlation coefficient

Answer

Pearson's correlation coefficient

Answer

Spearman's rank-order correlation coefficient

Answer

Cronbach's alpha

Question 4

Which measure of item discrimination compares the proportion of correct responses between high- and low-performing test takers?

Accepted Answer

Point-biserial correlation

Answer

Item Difficulty

Answer

KR-20 reliability

Answer

Cronbach's alpha

Question 5

The process of identifying items with poor discrimination is known as:

Accepted Answer

Item analysis

Answer

Reliability analysis

Answer

Validity analysis

Answer

Factor analysis

Question 6

Which item type typically shows higher discrimination?

Accepted Answer

Multiple-choice items

Answer

True-false items

Answer

Short answer items

Answer

Essay items

Question 7

To calculate item discrimination using the point-biserial correlation method, which formula should you use?

Accepted Answer

r_pb = (M_U - M_L) / SD_T

Answer

r_bis = (M_U - M_L) / SD_U

Answer

φ = (a + d - c - b) / (a + b + c + d)

Question 8

What is the primary purpose of item discrimination in educational assessments?

Accepted Answer

Distinguishing between students with high and low levels of knowledge or skills

Answer

Determining the difficulty of an assessment

Answer

Ensuring fairness in scoring

Answer

Calculating the reliability of an assessment tool

Question 9

Which of the following values represents a desirable level of item discrimination?

Accepted Answer

0.7

Answer

0.0

Answer

0.3

Answer

1.0

Question 10

How does item discrimination contribute to the overall quality of an assessment?

Accepted Answer

Increases reliability by identifying items that effectively differentiate between knowledgeable and less knowledgeable students

Answer

Guarantees equal difficulty across all items

Answer

Assesses the validity of the assessment

Answer

Determines appropriate cut scores

Question 11

Explain the role of item discrimination in developing effective assessments.

Accepted Answer

Helps identify items to include or exclude, ensuring a high-quality assessment

Answer

Guarantees equal difficulty for all items

Answer

Determines the reliability of an assessment

Answer

Assists in setting appropriate passing scores

Question 12

Acknowledge a limitation of item discrimination.

Accepted Answer

Can be influenced by factors like guessing and test anxiety

Answer

Does not assess the validity of an assessment

Answer

Is not a dependable indicator of item quality

Answer

Applicable only to multiple-choice items

Question 13

Describe how item discrimination enhances assessment quality.

Accepted Answer

Identifies items for revision or removal, leading to a stronger assessment

Answer

Guarantees equal difficulty for all items

Answer

Provides information on assessment reliability

Answer

Assists in setting appropriate cut scores

Question 14

To calculate the discrimination index for a binary item, use the formula:

Accepted Answer

(Upper - Lower) / (Upper + Lower)

Answer

(Upper + Lower) / (Upper - Lower)

Answer

Upper / Lower

Answer

Lower / Upper

Question 15

Point-biserial correlation is used for:

Accepted Answer

Binary items

Answer

Continuous items

Answer

Both binary and continuous items

Answer

Neither binary nor continuous items

Question 16

When is it appropriate to calculate item discrimination?

Accepted Answer

Both before and after using an item on a test

Answer

Before using an item on a test

Answer

After using an item on a test

Answer

Never

Question 17

A common method for calculating item discrimination for multiple-choice items is:

Accepted Answer

Point-biserial correlation

Answer

Tetrachoric correlation

Answer

Pearson product-moment correlation

Answer

Spearman's rank-order correlation

Question 18

What is the main benefit of using item discrimination in assessment?

Accepted Answer

Identifies items that distinguish between high- and low-achieving students

Answer

Enhances fairness and reduces bias

Answer

Increases the reliability of the entire assessment

Answer

Provides information about item difficulty and overall assessment difficulty

Question 19

What is the measure that determines an item's ability to differentiate between high- and low-performing test takers?

Accepted Answer

Item discrimination

Answer

Item difficulty

Answer

Item reliability

Answer

Item validity

Question 20

To calculate item discrimination using the point-biserial correlation, which formula should you use?

Accepted Answer

r_pb = (M_high - M_low) / (SD_high + SD_low)

Answer

r_pb = (M_high - M_low) / (SD_total)

Answer

r_pb = (M_total - M_high) / (SD_high)

Answer

r_pb = (M_total - M_low) / (SD_low)

Question 21

A low item discrimination index suggests that:

Accepted Answer

The item is ineffective at distinguishing between high and low performers.

Answer

The item effectively distinguishes between high and low performers.

Answer

The item is moderately effective at distinguishing between high and low performers.

Answer

The item is not reliable.

Question 22

The optimal value for item discrimination is:

Accepted Answer

1

Answer

0

Answer

0.5

Answer

-1

Question 23

Distinguish between item discrimination and item difficulty:

Accepted Answer

Item discrimination measures the ability of an item to differentiate test takers.

Answer

Item discrimination measures the difficulty of an item.

Answer

Item difficulty measures the ability of an item to differentiate test takers.

Answer

There is no difference between item discrimination and item difficulty.

Question 24

Which of the following is NOT an advantage of using item discrimination in test development?

Accepted Answer

Increasing the difficulty of a test

Answer

Identifying biased items

Answer

Improving the reliability of a test

Answer

Selecting items for a test

Question 25

What is the relationship between item discrimination and test reliability?

Accepted Answer

Items with high discrimination tend to increase test reliability

Answer

Items with low discrimination tend to increase test reliability

Answer

There is no relationship between item discrimination and test reliability

Answer

High discrimination items tend to decrease test reliability

Question 26

Which of the following statistical methods is most commonly used to calculate item discrimination?

Accepted Answer

Point-biserial correlation

Answer

Tetrachoric correlation

Answer

Biserial correlation

Answer

Pearson correlation

Question 27

Which of the following concepts measures the ability of an item to distinguish between high- and low-performing test takers?

Accepted Answer

Item discrimination

Answer

Item difficulty

Answer

Item reliability

Question 28

How is item discrimination typically calculated?

Accepted Answer

By comparing the proportion of correct responses between high- and low-scoring test-taker groups.

Answer

By calculating the mean and standard deviation of item scores.

Answer

By administering the item to a small sample of test takers.

Question 29

What is the ideal value for item discrimination?

Accepted Answer

1.0

Answer

0.0

Answer

0.5

Question 30

Which of the following is a key benefit of using item discrimination?

Accepted Answer

It helps identify items that are ineffective in differentiating test taker performance.

Answer

It reduces the length of a test.

Answer

It enhances the difficulty level of a test.

Question 31

How can item discrimination be utilized to enhance test quality?

Accepted Answer

By removing items with low discrimination values and adding items with high discrimination values.

Answer

By increasing the total number of items on the test.

Question 32

Which of the following is a potential limitation of item discrimination?

Accepted Answer

It can be influenced by the sample size used for its calculation.

Answer

It is a highly reliable measure of item quality.

Answer

It is only applicable to multiple-choice items.

Answer

It is not susceptible to item bias.

Question 33

Which factors are known to influence item discrimination?

Accepted Answer

Item format, item difficulty, and test-taker characteristics.

Answer

Only test-taker characteristics.

Answer

Only item format.

Question 34

Explain the relationship between item discrimination and test reliability.

Accepted Answer

Items with high discrimination values generally contribute more to the overall reliability of a test.

Answer

Item discrimination has no impact on test reliability.

Answer

Items with low discrimination values contribute more to test reliability.

Question 35

Which of the following formulas correctly calculates the Item Discrimination Index?

Accepted Answer

r_is = (p_u - p_l) / (q_u - q_l)

Answer

r_is = (p_u + p_l) / (q_u - q_l)

Answer

r_is = (p_u - p_l) / (q_u + q_l)

Answer

r_is = (p_u + p_l) / (q_u + q_l)

Question 36

A positive item discrimination index indicates:

Accepted Answer

The item effectively differentiates between high- and low-performing test takers.

Answer

The item is too easy for high-performing test takers.

Answer

The item is too challenging for low-performing test takers.

Question 37

Which factor does NOT influence item discrimination?

Accepted Answer

Test length

Answer

Item format

Answer

Item content

Answer

Item difficulty

Question 38

What is the primary purpose of using item discrimination indices in educational assessments?

Accepted Answer

To retain items that accurately measure the intended learning objectives.

Answer

To establish the difficulty level of a test

Answer

To estimate the reliability of a test

Question 39

How does the presence of guessing impact an item discrimination index?

Accepted Answer

Guessing typically reduces item discrimination indices.

Answer

Guessing has no effect on item discrimination indices.

Answer

Guessing increases item discrimination indices.

Question 40

What is the relationship between item difficulty and discrimination?

Accepted Answer

Items of intermediate difficulty often have higher discrimination indices compared to very easy or very difficult items.

Answer

Very easy items tend to have higher discrimination indices than items of intermediate or very difficult difficulty.

Question 41

What is a potential limitation of using item discrimination indices?

Accepted Answer

Item discrimination indices may be influenced by the sample size of the test takers.

Answer

Item discrimination indices are always reliable and accurate.

Answer

Item discrimination indices are not influenced by the subject matter of the test.

Question 42

Which of the following is a valid method for calculating item discrimination?

Accepted Answer

Point-biserial correlation

Answer

Item facility index

Answer

Tetrachoric correlation

Answer

Cronbach's alpha

Question 43

What is the purpose of calculating item discrimination?

Accepted Answer

To identify items that accurately differentiate between high- and low-performing test takers.

Answer

To determine the overall difficulty of a test

Answer

To calculate test reliability

Question 44

Which of the following is an advantage of using item discrimination?

Accepted Answer

Improved test validity

Answer

Increased test difficulty

Answer

Simplified scoring

Answer

Reduced testing time

Question 45

What is the relationship between item difficulty and item discrimination?

Accepted Answer

Items of moderate difficulty tend to exhibit higher discrimination than very easy or very difficult items.

Answer

Items of very easy difficulty tend to exhibit higher discrimination than items of moderate difficulty.

Question 46

How does guessing influence item discrimination?

Accepted Answer

Guessing can lower the discrimination of an item.

Answer

Guessing can improve the discrimination of an item.

Answer

Guessing only affects the difficulty of an item, not its discrimination.

Answer

Guessing has no impact on item discrimination.

Question 47

How can item discrimination data inform test improvement?

Accepted Answer

Items with low discrimination can be revised or removed to enhance the overall quality of the test.

Answer

Item discrimination data cannot be used to improve a test.

Answer

Items with high discrimination can be replaced with more difficult items

Question 48

Differentiate between item difficulty and item discrimination.

Accepted Answer

Item difficulty refers to the proportion of test-takers who answer an item correctly, whereas item discrimination measures an item's ability to differentiate between high- and low-performing test-takers.

Answer

Item difficulty and item discrimination are essentially the same concept.

Question 49

What is the primary purpose of analyzing item discrimination in educational assessments?

Accepted Answer

To determine how well a test item differentiates between students with varying levels of understanding.

Answer

To ensure all test items are equally challenging for the intended student population.

Question 50

If a test item has a high discrimination index, what does this indicate about its effectiveness?

Accepted Answer

The item effectively distinguishes between high-performing and low-performing students.

Answer

The item is very easy for all students, regardless of their understanding.

Answer

The item is very difficult for all students, regardless of their understanding.

Question 51

Which statistical method is commonly employed to calculate the discrimination index of a test item?

Accepted Answer

Point-biserial correlation

Answer

Cronbach's alpha

Answer

Standard error of measurement

Answer

T-test

Question 52

How would you categorize a test item with a discrimination index of 0.40?

Accepted Answer

Moderately discriminating

Answer

Not discriminating

Answer

Highly discriminating

Answer

Poorly discriminating

Question 53

During item analysis, you observe that high-performing students consistently answer a particular item correctly, while low-performing students consistently answer it incorrectly. What does this pattern suggest about the item's discrimination?

Accepted Answer

The item demonstrates high discrimination.

Answer

The item has high difficulty.

Answer

The item exhibits low discrimination.

Answer

The item has low difficulty.

Question 54

What does a negative discrimination index indicate about a test item?

Accepted Answer

Low-performing students are more likely to answer the item correctly than high-performing students.

Answer

The item is likely measuring a different construct than intended.

Answer

The item is too difficult for the intended student population.

Question 55

Which strategy can effectively improve the discrimination of a test item?

Accepted Answer

Ensure the distractor options are plausible and relevant to the item's content.

Answer

Simplify the item to make it as easy as possible for all students.

Answer

Include a larger number of irrelevant distractors.

Question 56

During a test review, you discover that several items have low discrimination indices. What is the most appropriate course of action?

Accepted Answer

Revise or replace the items with low discrimination to improve their ability to differentiate between students.

Answer

Disregard the low discrimination indices as they are not a significant concern.

Answer

Increase the difficulty of all items on the test to enhance overall challenge.

Question 57

Apart from item discrimination, what other psychometric properties are essential to consider when evaluating the quality of test items?

Accepted Answer

Reliability and validity

Answer

Accessibility and inclusivity

Answer

Cost-effectiveness and practicality of administration

Answer

Student satisfaction and engagement