Guess correction

The guess correction option of Ans uses the guess score of each question. The guess score of a question is the number of points a student statistically can score when guessing the question. First, Ans adds up all scores of each answer alternative. This number is divided by the number of answer alternatives. For example, you have multiple choice questions with four answer alternatives. One answer is correct and you can earn 1 point for the correct answer. The guess score is shown under Question within the Insights menu. 

The sum of all scores is: 0+0+0+1 = 1. The number of answer alternatives is 4. The guess score for this question is 1/4 = 0.25. The example above is a simple example. The calculation of the guess score becomes more complex when using different options of Ans, such as:

• Negative points per answer alternative
• Multiple correct answers
• Automatic scoring option
• Partial scoring option

When guess correction is enabled for a question with negative points for incorrect alternatives the negative points are not taken into account. This prevents any unintentional double deductions of negative points and stops the guess score from being deducted twice. When all guess scores are calculated, Ans sums all guess scores to get to the assignment guess score.

The guess score of bonus questions is still taken into account for the assignment guess score correction. The guess score of full points and disabled questions is not taken into account for the guess score correction.

The score is visible under Insights of the assignment. Further below in this article are examples of how the guess score is calculated for each question type or variant within a question type.

Ans has two mark calculation types in which the guess correction can be used: formula and table. For each of the mark calculation types, the application of the guess correction is explained in further detail below.

To apply the guess correction on the mark calculation of your assignment, follow the steps below.

You can now choose to apply the guess correction on both available mark calculation methods: formula and table.

Guess correction using the formula

If a formula is used, the guess correction can be applied by using the checkboxes:

• Guess correction
  When enabling this checkbox, the guess correction is taken into account to calculate the mark. In this case, the corrected score is used to calculate the number of points.
• Limit the guess correction to zero
  When this option is enabled, the corrected score after applying the guess correction cannot be lower than 0. This option can be used if an assignment has questions that can be corrected and questions that cannot be corrected. 
• Apply guess correction to answered questions only
  With this option enabled, unanswered questions will not have the guess correction applied to them.

In the formula, you can use the variables 'points' and 'total' as explained in the article Calculate a mark. When using the guess correction option, Ans will use the corrected score to calculate the mark. The corrected scores are not shown in the platform. If you want to see examples on how the different settings for the mark calculation can be applied in the platform, you can take a look at this article. 

Guess correction using the table

The table mark calculation does not have the checkbox option like the formula. Within the table, you can change either the lowest amount of points or the cut-off score to include the guess correction. If you want to limit the guess correction to 0, for example, if you have an exam with both guess correction question types and other question types, the formula is a better method.

• If you change the lowest score to the guess score of the assignment, participants will need to score the guess score to get the lowest mark. From there on, students will start scoring higher marks.
• Another option to incorporate the guess correction in the table method is to change the cut-off score. A frequently used formula to calculate the cut-off score with the guess correction included is:
  • Cut-off score based on guessing score = (maximum score - guessing score)*cut-off score + guess score

One of the questions that are used most frequently in combination with the guess correction in Ans is the multiple choice question. The multiple choice question can have either 1 or multiple correct answers. For each of them, an example is provided.

Multiple choice: 1 correct answer

For the multiple choice question with 1 correct answer, we use the same example as mentioned above under the 'The question guess score' section.

• Number of answer alternatives: 4
• Correct Answer: A
• Points to be earned: 1

To calculate the guess correction, the scores per answer alternative are calculated:

Guess score = sum of all scores / # alternatives.

Multiple choice: multiple correct answers

The calculation of the guess score for a multiple choice question with multiple correct answers is more complex. The score depends on multiple factors, such as partial scoring and automatic scoring. The following example is provided:

• Number of answer alternatives: 4
• Correct answers: A and B
• Points to be earned: 2 (1 for A and 1 for B)

To calculate the guess correction, the scores per answer alternative are calculated. If you want to know more about how the scores with automatic scoring are calculated, you can check this article.

Guess score = sum of all scores / # alternatives.

The match question is the most complicated question to calculate the guess score for. There are four different types of match questions. They all have their own way of calculating the guess score:

• 1 correct answer, matrix layout
• 1 correct answer, drag-and-drop layout
• Multiple correct answers, matrix layout
• Multiple correct answers, drag-and-drop layout

The main reason for different calculations is that for the drag-and-drop layout, each time a choice is made, automatically other choices cannot be made anymore. For all four types, the partial scoring option can be used. Also, the automatic scoring option can be used for the two types where multiple answers are correct. An example is provided per match question type. To calculate the number of answer alternatives, Ans counts the number of unique answer combinations when all rows are filled in. Leaving a row empty is not considered as an alternative in calculating the number of answer possibilities.

error_outline To optimise performance, two limits are applied when calculating the guess score for match questions. If a row or column contains more than 4 entities, the guess score is calculated per row, and all rows are summed to calculate the overall guess score for the question. If a row or column contains more than 10 entities, the guess score is equal to 0.

Match: 1 correct answer, matrix layout:

The calculation of this question type is similar to the calculation of the multiple choice, 1 answer correct question type.

• Number of rows (R): 2
• Number of columns (C): 2
• Correct answers: R1C1 & R2C2
• Points to be earned: 2 (1 per match)

Guess score = sum of all scores / # alternatives.

Match: 1 correct answer, drag-and-drop layout:

For the drag-and-drop layout of the match question, the number of answer alternatives is lower. As there is 1 correct answer, for each time a choice (column) is dragged (row), it's not possible to drag another choice to the same row. We will explain this with the same example as above.

• Number of rows (R): 2
• Number of columns (C): 2
• Correct answers: R1C1 & R2C2
• Points to be earned: 2 (1 per match)

Guess score = sum of all scores / # alternatives.

Match: multiple correct answers, matrix layout:

Just like a matrix layout with 1 correct answer, the calculation of the number of answer alternatives is similar to a multiple choice question (with multiple correct answers). We will keep using the same example as the other match question examples. As there are multiple answers correct, the automatic scoring option can be used as well.

• Number of rows (R): 2
• Number of columns (C): 2
• Correct answers: R1C1 & R2C2
• Points to be earned: 2 (1 per match)

Guess score = sum of all scores / # alternatives.

Match: multiple correct answers, drag-and-drop layout:

The fourth and last match question type is the drag-and-drop layout with multiple correct answers. Again, the same example is used. the main difference with the other match question types is that a student can drag multiple alternatives (columns) to the same row.

• Number of rows (R): 2
• Number of columns (C): 2
• Correct answers: R1C1 & R2C2
• Points to be earned: 2 (1 per match)

Guess score = sum of all scores / # alternatives.

For the fill-in question, it is possible to calculate a guess score. This is only possible when the option 'show answer' is used. By using this option, the answer layout for a student changes. By default, the student can type the answer in a textbox. If the show answer option is enabled, the student will see a dropdown menu. The right answer needs to be chosen by selecting an answer. The guess score for a fill-in question is only calculated up to 1024 possible permutations (combinations).
If there are more combinations, a guess score of 0 will be returned.

A free field within a fill-in question looks like this: 

A dropdown menu in a fill-in question looks like this:

There are two possibilities when using a fill-in question which changes the calculation of the guess score. There can be 1 gap or multiple gaps in one question. An example of each possibility is provided.

Fill-in: 1 gap

The guess score for a fill-in question with 1 gap is calculated in the same way as a multiple choice question with 1 correct answer. For the fill-in question, the student can also select 1 option out of the given options. We changed the multiple choice example given above to a fill-in question.

• Number of answer alternatives: 4
• Correct Answer: A
• Points to be earned: 1

To calculate the guess correction, the scores per answer alternative are calculated:

Guess score = sum of all scores / # alternatives.

Fill-in: multiple gaps

When using multiple gaps, the guess score calculation changes slightly. Also, the partial scoring rule can be applied. The automatic scoring can also be enabled, however, for the fill-in question this only means an even distribution of the scores over the correct answer alternatives. Therefore, this has no impact on the calculation of the guess score. The automatic scoring option will be left outside this example. For the calculation of the guess scores, Ans checks all possible answer combinations.If an answer is left empty, it is not calculated as a possibility for the guess score calculation.

• Number of gaps: 2
• Number of answer alternatives per gap: 3
• Correct answer: A for gap 1 and D for gap 2
• Points to be earned: 2 (1 point per correct gap)

Guess score = sum of all scores / # alternatives.

For the order question, Ans checks the possible pairs of answer options. For each pair, the position of an answer compared with another answer is checked. For example, an order question with three answer possibilities is used. For the order question, both partial scoring and automatic scoring can be used.

• Number of answer alternatives: 3
• Correct answer: A-B-C
• Points to be earned: 1

For this example, the following pairs are possible:

With this information, Ans can calculate the guess scores. 

Guess score = sum of all scores / # alternatives.