In this article, the guess correction is explained. The guess correction is an option to correct the score of a student. The option can be used within the mark calculation of an assignment. This article does not give any explanation on the calculation of a grade with guess correction. To find examples of mark calculations, please refer to this article.
The purpose of the guess correction is to set a threshold for students that they will need to pass in order to score a mark. We explain the guess correction with a relatively easy example. You created an assignment with 40 multiplechoice questions. Per question, the student can earn 1 point, so the maximum score is 40 points. Each question is a multiple choice question with 4 answer alternatives out of which 1 is correct. The chance of guessing the right answer is 25%. Therefore, the guess correction threshold is 10 points (25% of 40 points). This means each student with a score of 10 or lower will receive the lowest mark. The distribution of the marks (typically on a 110 scale) will start from 11 points onwards.
In Ans, the guess correction can be used for both the formula and the table mark calculation. The formula has a checkbox which allows enables the guess correction automatically. For the table, you will need to insert the guess correction manually. In this article, we explain how you can do this. The guess correction can only be applied when at least one of the following question types is used in an assignment:
 Fillin (if the ‘show answer’ option is enabled)
 Multiple choice (both one correct answer and multiple answers)
 Match
 Order
The hotspot and hotspot match questions are closedended questions as well. However, it is difficult to calculate the number of incorrect options for these questions. The guess correction does not take these question types into account.
If the guess correction option is used, Ans corrects the score of the student for all the question types mentioned above. For all other question types, such as openended questions, the score is not corrected, as the student cannot guess the correct answer. The formula to calculate the corrected score is:
 Corrected score = (MSG * ((TSG  GS) / (MSG  GS))) + TSO
In this formula:
 MSG:
 Maximum score guess correction questions = the maximum possible score of all question types where guess correction is applied on
 TSG:
 Total score guess correction questions = the sum of all scores of the question types where guess correction is applied on
 GS:
 Guess score = the sum of all guess scores of each question (see calculation below)
 TSO:
 Total score other questions = the sum of all scores of question types where no guess correction is applied on.
The corrected score is used to calculate the mark of the student. Please note that the corrected score is not visible in the platform.
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 all guess scores are calculated, Ans sums all guess scores to get to the assignment guess score. 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.
 Click the domain School name in the menu on the left.
 Click label_important Courses in the menu at the top.
 Select your course or use the search bar.
 Select your assignment or use the search bar.
 Click settings Settings in the menu at the top.
 Click on Mark calculation in the menu on the left.
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 in case 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 cutoff score to include the guess correction. In case 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 cutoff score. A frequently used formula to calculate the cutoff score with the guess correction included is:
 Cutoff score based on guessing score = (maximum score  guessing score)*cutoff score + guess score
Examples of guess score calculations
For each question type where Ans can calculate the guess score, examples of the guess score calculations are provided further in this part of the article. For all examples, we left negative points per answer alternative out of scope, as this makes the calculation more complex. The formula mentioned above to calculate the question guess score can be applied with negative scores as well.
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:
Answer  Score 
A  1 
B  0 
C  0 
D  0 
Guess score  1 / 4 = 0.25 
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.
Answer  Partial scoring off  Partial scoring on, automatic scoring off  Partial scoring on, automatic scoring on 
A  0  1  1 
B  0  1  1 
C  0  0  0 
D  0  0  0 
AB  2  2  2 
AC  0  1  0,625 
AD  0  1  0,625 
BC  0  1  0,625 
BD  0  1  0,625 
CD  0  0  0 
ABC  2  2  1,25 
ABD  2  2  1,25 
ACD  0  1  0,25 
BCD  0  1  0,25 
ABCD  2  2  0,5 
Guess score  8 / 15 = 0,5333  16 / 15 = 1,0666  10 / 15 = 0,6666 
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, draganddrop layout
 Multiple correct answers, matrix layout
 Multiple correct answers, draganddrop layout
The main reason for different calculations is that for the draganddrop 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 Due to performance reasons, two limits apply for calculating the guess score for match questions:
In case a row or column is larger than 4 entities, a guess score is calculated per row. All rows are summed to calculate the guess score of the question.
In case a row or column has 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 multiplechoice, 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)
Answer  Partial scoring off  Partial scoring on 
R1C1, R2C1  0  1 
R1C1, R2C2  2  2 
R1C2, R2C1  0  0 
R1C2, R2C2  0  1 
Guess score  2 / 4 = 0.5  4 / 4 = 1 
Guess score = sum of all scores / # alternatives.
Match: 1 correct answer, draganddrop layout:
For the draganddrop 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)
Answer  Partial scoring off  Partial scoring on 
R1C1, R2C2  2  2 
R1C2, R2C1  0  0 
Guess score  2 / 2 = 1  2 / 2 = 1 
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)
Answer  Partial scoring off 
Partial scoring on, automatic scoring off  Partial scoring on, automatic scoring on 
R1C1  0  1  1 
R1C2  0  0  0 
R2C1  0  0  0 
R2C2  0  1  1 
R1C1, R1C2  0  1  0 
R1C1, R1C2  0  1  0 
R1C1, R2C1  0  1  0.625 
R1C1, R2C2  2  2  2 
R1C2, R2C1  0  0  0 
R1C2, R2C2  0  1  0.625 
R2C1, R2C2  0  1  0.625 
R1C1, R1C2, R2C1  0  1  0.25 
R1C1, R1C2, R2C2  2  2  1.25 
R1C1, R2C1, R2C2  2  2  1.25 
R1C2, R2C1, R2C2  0  1  0.625 
R1C1, R1C2, R2C1, R2C2  2  2  0.5 
R1C1, R1C2, R2C1, R2C2  2  2  0.5 
Guess score  8 / 15 = 0,5333  16 / 15 = 1,0666  10,375 / 15 = 0,6916 
Guess score = sum of all scores / # alternatives.
Match: multiple correct answers, draganddrop layout:
The fourth and last match question type is the draganddrop 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)
Answer  Partial scoring off  Partial scoring on, automatic scoring off  Partial scoring on, automatic scoring on 
R1C1, R1C2  0  1  0,625 
R1C1, R2C2  2  2  2 
R1C2, R2C1  0  0  0 
R2C1, R2C2  0  1  0.625 
Guess score  2 / 4 = 0.5  4 / 4 = 1  3.25 / 4 = 0.8215 
Guess score = sum of all scores / # alternatives.
For the fillin 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. In case 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 fillin 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 fillin question looks like this:
A dropdown menu in a fillin question looks like this:
There are two possibilities when using a fillin 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.
Fillin: 1 gap
The guess score for a fillin question with 1 gap is calculated in the same way as a multiple choice question with 1 correct answer. For the fillin question, the student can also select 1 option out of the given options. We changed the multiplechoice example given above to a fillin 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:
Answer  Score 
A  1 
B  0 
C  0 
D  0 
Guess score  1 / 4 = 0.25 
Guess score = sum of all scores / # alternatives.
Fillin: 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 fillin 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. In case 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)
Answer  Partial scoring off  Partial scoring on 
A  D  2  2 
A  E  0  1 
A  F  0  1 
B  D  0  1 
B  E  0  0 
B  F  0  0 
C  D  0  1 
C  E  0  0 
C  F  0  0 
Guess score  2 / 9 = 0,22222  6 / 9 = 0,66666 
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: ABC
 Points to be earned: 1
For this example, the following pairs are possible:
Pair  Letter grade 
A  B  Correct 
A  C  Correct 
B  A  Incorrect 
B  C  Correct 
C  A  Incorrect 
C  B  Incorrect 
With this information, Ans can calculate the guess scores.
Pair  Partial scoring off  Partial scoring on, automatic scoring off  Partial scoring on, automatic scoring on 
A  B  C  1  3/3 correct: 1  3/3 correct, 0/3 incorrect: 1 
A  C  B  0  2/3 correct: 0.66666  2/3 correct, 1/3 incorrect: 0.66666 
B  A  C  0  2/3 correct: 0.66666  2/3 correct, 1/3 incorrect: 0.66666 
B  C  A  0  1/3 correct: 0.33333  1/3 correct, 2/3 incorrect: 0.33333 
C  A  B  0  1/3 correct: 0.33333  1/3 correct, 2/3 incorrect: 0.33333 
C  B  A  0  0/3 correct: 0  0/3 correct, 3/3 incorrect: 0 
Guess score  1 / 6 = 0.16666  3 / 6 = 0.5  3 / 6= 0.5 
Guess score = sum of all scores / # alternatives.
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