The checkbox problem type is a core problem type that can be added to any
course. At a minimum, checkbox problems include a question or prompt and
several answer options. By adding hints, feedback, or both, you can give
learners guidance and help when they work on a problem.

In checkbox problems, learners select one or more options from a list of
possible answers. To answer the problem correctly, a learner must select all
of the options that are correct answers, and none of the options that are
incorrect. The course team must set up each checkbox problem to have at least
one correct answer.

As a best practice, be sure that all of the answer choices are unambiguous, and
avoid trick questions. Checkbox problems with ambiguity can be frustrating to
learners, especially if the problems have a limited number of attempts.

In the LMS, learners complete a checkbox problem by selecting the answer
options that they believe are correct as well as leaving unselected the answer
options that they believe are incorrect. An example of a completed checkbox
problem follows.

This problem was incorrectly answered because the learner selected only two of
the three required answer options. This example also shows that the learner
selected Show Answer to reveal the correct answer and an explanation.

To add the example problem illustrated above, in Studio you use the simple
editor to enter the following text and Markdown formatting.

>>Learningaboutthebenefitsofpreventativehealthcarecanbeparticularlydifficult.||Checkalloftheoptionsbelowthatmightbereasonswhy.<<[x]Alargeamountoftimepassesbetweenundertakingapreventativemeasureandseeingtheresult.[]Non-immunizedpeoplewillalwaysfallsick.[x]Ifothersareimmunized,fewerpeoplewillfallsickregardlessofaparticularindividual's choice to get immunized or not.[x]Trustinhealthcareprofessionalsandgovernmentofficialsisfragile.[explanation]Peoplewhoarenotimmunizedagainstadiseasemightstillnotfallsickfromthedisease.Ifsomeoneistryingtolearnwhetherornotpreventativemeasuresagainstthediseasehaveanyimpact,heorshemightseethesepeopleandconclude,sincetheyhaveremainedhealthydespitenotbeingimmunized,thatimmunizationshavenoeffect.Consequently,heorshewouldtendtobelievethatimmunization(orotherpreventativemeasures)havefewerbenefitsthantheyactuallydo.[explanation]

<problem><choiceresponse><label>Learning about the benefits of preventative health care can be
particularly difficult.</label><description>Check all of the options below that might be reasons why.</description><checkboxgroup><choicecorrect="true">A large amount of time passes between
undertaking a preventative measure and seeing the result.</choice><choicecorrect="false">Non-immunized people will always fall sick.</choice><choicecorrect="true">If others are immunized, fewer people will fall
sick regardless of a particular individual's choice to get immunized
or not.</choice><choicecorrect="true">Trust in health care professionals and
government officials is fragile.</choice></checkboxgroup><solution><divclass="detailed-solution"><p>Explanation</p><p>People who are not immunized against a disease might still not
fall sick from the disease. If someone is trying to learn whether
or not preventative measures against the disease have any impact,
he or she might see these people and conclude, since they have
remained healthy despite not being immunized, that immunizations
have no effect. Consequently, he or she would tend to believe that
immunization (or other preventative measures) have fewer benefits
than they actually do.</p></div></solution></choiceresponse></problem>

You can begin work on the problem in the simple editor, and then
switch to the advanced editor. However, after you save any changes you make
in the advanced editor, you cannot switch back to the simple editor.

For an overview of feedback in problems, see Adding Feedback and Hints to a Problem. For checkbox problems, you can add feedback for each of the answer
options you provide in the problem. You can also identify different
combinations of answer options that learners are likely to select, and add
compound feedback for those combinations.

You can add feedback to a checkbox problem using the simple editor
or the advanced editor.

In checkbox problems, you can provide feedback for each option that a learner
can select, with distinct feedback depending on whether or not the learner
selects that option. This means that there are several possible types of
feedback.

The learner selects a correct option. This type of feedback
should indicate why the option is correct.

The learner does not select a correct option. This type of feedback should
indicate that the learner missed checking this option and why it is correct.

The learner selects an incorrect option. This type of feedback should
indicate that the learner incorrectly checked this option and why it is
incorrect.

The learner does not select an incorrect option. This type of feedback should
reinforce why the learner correctly left this option unselected.

You can configure the checkbox problem to provide compound feedback.
Compound feedback is feedback given for a specific combination of options. For
example, if you have three possible option in the problem, you can define
specific feedback for when a learner selects each combination of possible
options.

A

B

C

A, B

B, C

A, C

A, B, C

For problems with more than three options, providing specific feedback for each
combination can become difficult. For such problems, you might choose to define
compound feedback for more likely combinations of option or for combinations of
option that reflect common learner misunderstandings. If you do not define
feedback for a combination that a learner selects, the learner receives
feedback for the individual selections.

You can configure individual option or compound feedback in the simple
editor. When you create a new checkbox problem, select the
template Checkboxes with Hints and Feedback. This template has example
formatted feedback that you can replace with your own text.

For example, the following problem has feedback for every answer option,
whether learners select a given option or leave it unselected.

>>Which of the following is an example of a fruit?||Select all that apply.<<
[x] apple {{ selected: You are correct that an apple is a fruit because it
is the fertilized ovary that comes from an apple tree and contains seeds. },
{ unselected: Remember that an apple is also a fruit.}}
[x] pumpkin {{ selected: You are correct that a pumpkin is a fruit because it
is the fertilized ovary of a squash plant and contains seeds.}, { unselected:
Remember that a pumpkin is also a fruit.}}
[ ] potato {{ U: You are correct that a potato is a vegetable because it is
an edible part of a plant in tuber form.}, { S: A potato is a vegetable, not
a fruit, because it does not come from the flower on a plant or tree and does
not contain seeds.}}
[x] tomato {{ S: You are correct that a tomato is a fruit because it is the
fertilized ovary of a tomato plant and contains seeds. }, { U: Many people
mistakenly think a tomato is a vegetable. However, because a tomato is the
fertilized ovary of a tomato plant and contains seeds it is classified as a
fruit.}}

If you configure individual option feedback for every answer, and
you also provide compound feedback, when learners select the exact
combination of answer choices defined, they only see the compound feedback.
In this example, learners who select apple (A), pumpkin (B), and tomato (D)
see the message “An apple, pumpkin, and tomato are all fruits as they are all
the fertilized ovaries of a plant and contain seeds.” They do not also see
the individual feedback for selecting A, B, and D, and for leaving C
unselected.

In the advanced editor, you configure individual option feedback with the
following syntax.

<choicecorrect="true">Choice label
<choicehintselected="true">Feedback for when learner selects this
answer.</choicehint><choicehintselected="false">Feedback for when learner does not select
this answer.</choicehint></choice>

For example, the following problem has feedback for each option, selected or
unselected.

<problem><choiceresponse><label>Which of the following is an example of a fruit?</label><description>Select all that apply.</description><checkboxgroup><choicecorrect="true">apple
<choicehintselected="true">You are correct that an apple is a fruit
because it is the fertilized ovary that comes from an apple tree and
contains seeds.</choicehint><choicehintselected="false">Remember that an apple is also a
fruit.</choicehint></choice><choicecorrect="true">pumpkin
<choicehintselected="true">You are correct that a pumpkin is a fruit
because it is the fertilized ovary of a squash plant and contains
seeds.</choicehint><choicehintselected="false">Remember that a pumpkin is also a
fruit. </choicehint></choice><choicecorrect="false">potato
<choicehintselected="true">A potato is a vegetable, not a fruit,
because it does not come from the flower on a plant or tree and does
not contain seeds.</choicehint><choicehintselected="false">You are correct that a potato is
classified as a vegetable because it is an edible part of a plant in
tuber form.</choicehint></choice><choicecorrect="true">tomato
<choicehintselected="true">You are correct that a tomato is
classified as a fruit because it is the fertilized ovary of a tomato
plant and contains seeds.</choicehint><choicehintselected="false">Many people mistakenly think a tomato is
a vegetable. However, because a tomato is the fertilized ovary of a
tomato plant and contains seeds it is classified as a fruit.</choicehint></choice></checkboxgroup></choiceresponse></problem>

For example, the following compound feedback is used when learners select
options A, B, and D or A, B, C, and D.

.
.
.
</choice><compoundhintvalue="A B D">An apple, pumpkin, and tomato are all
fruits as they all are fertilized ovaries of a plant and contain
seeds.</compoundhint><compoundhintvalue="A B C D">You are correct that an apple, pumpkin,
and tomato are all fruits as they all are fertilized ovaries of a
plant and contain seeds. However, a potato is not a fruit as it is an
edible part of a plant in tuber form and is classified as a vegetable.
</compoundhint></checkboxgroup>

In the following example, the learner selected two of the three correct
choices, and did not select any incorrect choices. The learner therefore had
four out of five correct answers. Because the course team set this problem up
to award partial credit for every correct answer selected and every incorrect
answer left unselected (known as every decision counts), the learner earned
80% of the points for this problem.

You can use the following methods to award partial credit in a checkbox
problem.

You can configure a checkbox problem so that every selection a learner makes for
the checkbox problem is evaluated and scored. This method is known as every
decision counts (EDC).

With EDC, if “n” is the number of possible options, learners earn 1/n of the
total possible score for each correct option they select. Learners receive
partial credit for every correct answer selected and every incorrect answer left
unselected.

For example, if there are four options, every option that a learner matches is
worth 25% of the total score. A learner also gains 25% for each incorrect answer
that a learner does NOT select.

The following table shows how the different combinations of learner selections
would score for one EDC problem whose answers are as follows.

Correct options: A, B, D

Incorrect options: C

Learner’s Selections

Score

Explanation

A, B, D

100%

The learner matched each of the 3 correct answers for 75%, and also
gained 25% for not selecting the incorrect answer.

A, B

75%

The learner matched 2 of the correct answers for 50%, and also gained
25% for not selecting the incorrect answer.

A, B, C

50%

The learner matched 2 of the correct answers for 50%, but selected the
incorrect answer.

A, C

25%

The learner matched 1 of the correct answers for 25%, but selected the
incorrect answer.

To configure an EDC checkbox problem, you add the partial_credit="EDC"
attribute to the <choiceresponse> element in the problem OLX.

For example, the following OLX shows the checkbox problem template after it is
updated to provide partial credit.

<problem><choiceresponsepartial_credit="EDC"><label>Which of the following is a fruit?</label><description>Select all that apply.</description><checkboxgroup><choicecorrect="true">apple</choice><choicecorrect="true">pumpkin</choice><choicecorrect="false">potato</choice><choicecorrect="true">tomato</choice></checkboxgroup></choiceresponse></problem>

You can configure a checkbox problem so that for every option that a learner
gets wrong, either by not selecting a correct option or by selecting an
incorrect option, half of the remaining points are deducted from the learner’s
score. This method is known as scoring by halves.

Note

By design, partial credit by halves requires the number of answer
options to be more than twice the number of incorrect answers. In addition,
partial credit is not given for more than two wrong answers, regardless of
the total number of answer options. In other words, two wrong answers is
scored at 25% only if there are at least 5 answer options. Three or more
wrong answers is always scored at 0%, regardless of the number of total
answer options.

Partial credit using the by halves method is calculated as follows.

If a learner makes no errors, she receives full credit for the problem.

If a learner makes one error, she receives 50% of the possible points, as
long as there are three or more choices in the problem. If a learner makes
one error and there are only two choices in the problem, no credit is given.

If a learner makes two errors, she receives 25% of the possible points, as
long as there are five or more choices in the problem. If a learner makes two
errors and there are only three choices or four choices in the problem, no
credit is given.

If a learner makes three errors, she receives no credit for the problem,
regardless of how many answer options there are.

The following tables illustrate partial credit score using the halves method,
for problems with an increasing number of total answer options.

To configure a by halves checkbox problem, you add the
partial_credit="halves" attribute to the <choiceresponse> element in
the problem OLX.

The following example shows a checkbox problem that provides partial credit by
halves.

<problem><choiceresponsepartial_credit="halves"><label>Which of the following is a fruit?</label><description>Select all that apply.</description><checkboxgroup><choicecorrect="true">apple</choice><choicecorrect="true">pumpkin</choice><choicecorrect="false">potato</choice><choicecorrect="true">tomato</choice></checkboxgroup></choiceresponse></problem>

<problem><choiceresponse><label>Question or prompt text</label><description>Information about how to answer the question</description><checkboxgroup><choicecorrect="false">Answer option A (incorrect)</choice><choicecorrect="true">Answer option B (correct)</choice><choicecorrect="true">Answer option C (correct)</choice></checkboxgroup><solution><divclass="detailed-solution"><p>Optional header for the explanation or solution</p><p>Optional explanation or solution text</p></div></solution></choiceresponse><demandhint><hint>Hint 1</hint><hint>Hint 2</hint></demandhint></problem>

You can use the <script> element to programmatically set attributes and
options for your checkbox problems. You could use this feature to display
different questions/answers depending on variable factors, like time of day, or
randomly generated numbers.