Psychometrics API data: CTT data sources

  • Uppdaterad

Test taker stats

This data source provides test taker-level CTT metrics summarising overall performance on the test. It is based on submitted data.

ColumnDescriptionExample
item_bank_idID of the Item Bank that this item belongs to.137279203
item_bank_nameName of the Item Bank that this item belongs to.Demo item bank
assessment_run_id

The ID of the assessment run (i.e specific test). Each assessment has a unique assessment_run_id.

This ID is a combination of a set of questions, a specific time when this assessment is run, and a group of users that are taking this test.

137465023
assessment_start_time

Timestamp of assessment run’s start time.

This is not the individual start time for each test taker, often all test takers who took the same assessment have the same assessment_start_time.

2025-12-04T07:00:00.000Z
assessment_end_time

Timestamp of assessment run’s end time.

This is not the individual end time for each test taker, often all test takers who took the same assessment have the same assessment_end_time.

2025-12-04T07:35:00.000Z
user_idID of the test taker who made a submission for the assessment.137465032
global_person_idA unique identifier that allows us to identify the user across different test sittings in the Inspera platform1357554-137465032
user_external_idExternal ID for the user137465032
user_assessment_idID for the user's assessment instance9939406
run_identifierUnique identifier for the run2a88a5a9-42c3-4d5a-b938-3fe68832fc92
test_taker_total_scoreThe total score attained by a test taker on the assessment.3
row_timestamp

The time of which this record was generated. Upon conflicts the record with the latest row_timestamp will always be used.

Format is yyyy-MM-ddTHH:mm:ssZ

2025-12-04T07:42:43.783Z

 

Item stats

This data source provides the core CTT item-level metrics, allowing for detailed psychometric evaluation of every question and response interaction.

ColumnDescriptionExample

item_bank_id

ID of the Item Bank that this item belongs to.

137279203

item_bank_name

Name of the Item Bank that this item belongs to.

Demo item bank

assessment_run_id

The ID of the assessment run (i.e specific test). Each assessment has a unique assessment_run_id.

This ID is a combination of a set of questions, a specific time when this assessment is run, and a group of users that are taking this test.

137465023

run_identifier

Unique identifier for the run

2025-12-04T07:00:00.000Z

section_content_item_id

ID for the section content item

2025-12-04T07:35:00.000Z

question_content_item_id

The unique ID for the question

137456120

measure_id

ID for the measure

909486

response_variable_interaction_id

ID for the response variable interaction

RESPONSE

interaction_response_identifier

Identifier for the interaction response

RESPONSE

question_type

The type of the question (e.g. multiple choice)

content_question_qti2_multiple_choice

question_order

The order of the question

3

interaction_order_in_question

The order of the interaction within the question

1

exposure

Number of test takers who have seen the question, regardless of whether they answered.

2a88a5a9-42c3-4d5a-b938-3fe68832fc92

interaction_answered

Number of test takers who answered the interaction.

1

question_answered

Number of test takers who answered the question. A question is answered iif at least one of its interactions is answered.

1

interaction_omitted

Number of test takers who have seen the interaction but did not answer it.

1

question_omitted

Number of test takers who have seen the question but did not answer it.

0

not_reached

Number of test takers who were supposed to see the question but did not.

0

question_average_time_spent_seconds

Average time spent on a question, taking into account only exposed students

0

interaction_max_score

Theoretical Max score possible for the interaction.

1

interaction_mean_score

Mean score obtained for the interaction.

1

interaction_score_stdev

Standard deviation of the scores obtained for the interaction.

0

interaction_mean_score_se

Standard error of the mean score obtained for the interaction.

0

interaction_facility

Facility of the interaction. It measures the proportion of students who answered a question correctly. Range between 0 and 1.

1

interaction_facility_se

Standard error of the facility of the interaction.

0

interaction_discrimination

Discrimination of the interaction. It measures how well the item discriminates between students of high and low ability. It ranges between -1 and 1. Negative or very low positive values ​​may indicate that the question does not discriminate well between students of high and low ability.

0

interaction_discrimination_corrected

Discrimination of the interaction corrected by removing the score of the present interaction from the total score.

0

question_max_score

Theoretical Max score possible for the question.

1

question_mean_score

Mean score obtained for the question.

1

question_score_stdev

Standard deviation of the scores obtained for the question.

0

question_mean_score_se

Standard error of the mean score obtained for the question.

0

question_facility

Facility of the question.

1

question_facility_se

Standard error of the facility of the question.

0

question_discrimination

Discrimination of the question.

0

question_discrimination_corrected

Discrimination of the question corrected by removing the score of the present question from the total score.

0
row_timestamp

The time of which this record was generated. Upon conflicts the record with the latest row_timestamp will always be used.

Format is yyyy-MM-ddTHH:mm:ssZ

2025-12-04T07:42:43.783Z

 

Assessment stats

This data source provides reliability and score distribution metrics calculated at the overall test level. It provides essential evidence regarding the internal consistency and spread of scores for the entire assessment.

ColumnDescriptionExample

item_bank_id

ID of the Item Bank that this item belongs to.

137279203

item_bank_name

Name of the Item Bank that this item belongs to.

Demo item bank

assessment_run_id

The ID of the assessment run (i.e specific test). Each assessment has a unique assessment_run_id.

This ID is a combination of a set of questions, a specific time when this assessment is run, and a group of users that are taking this test.

137465023

assessment_start_time

Timestamp of assessment run’s start time.

This is not the individual start time for each test taker, often all test takers who took the same assessment have the same assessment_start_time.

2025-12-04T07:00:00.000Z

assessment_end_time

Timestamp of assessment run’s start time.

This is not the individual start time for each test taker, often all test takers who took the same assessment have the same assessment_start_time.

2025-12-04T07:35:00.000Z
run_identifierUnique identifier for the specific calculation.2a88a5a9-42c3-4d5a-b938-3fe68832fc92
number_test_takers_enrolledNumber of test takers enrolled in an assessment.5
number_test_takers_submittedNumber of test takers who submitted the assessment.1

min_score

Minimum score obtained on the assessment.

3

max_score

Maximum score obtained on the assessment.

3

mean_score

Mean score obtained on the assessment.

3

score_stdev

Standard deviation of scores obtained on the assessment.

0

total_score_q1

1st percentile of the scores of all test takers who submitted this assessment.

3

total_score_q2

2nd percentile of the scores of all test takers who submitted this assessment.

3

total_score_q3

3rd percentile of the scores of all test takers who submitted this assessment.

3
interaction_level_cronbach_alphaReliability calculated at the interaction level.0
question_level_cronbach_alphaReliability calculated at the question level.0
total_score_histogram.number_test_takersList of the number of test takers (x axis) in a histogram plot of total score v/s number of test takers.[0,0,0,1,0]
total_score_histogram.total_scoreList of the total score (y axis) corresponding to each item in the number of test takers list above.[0,1,2,3,4]
exposure_histogram.question_orderList of the question order (x axis) in a histogram plot of the exposure count v/s question order.[1,2,3,4]
exposure_histogram.exposure

List of the exposure count (y axis) corresponding to each item in the question order list above.

Exposure count is the number of test takers who have viewed a question.

[1,1,1,1]
answered_histogram.question_orderList of the question order (x axis) in a histogram plot of the answered count v/s question order.[1,2,3,4]
answered_histogram.answered

List of the answered count (y axis) corresponding to each item in the question order list above.

Answered count is the number of test takers who have answered a question.

[1,1,1,1]
omitted_histogram.question_orderList of the question order (x axis) in a histogram plot of the omitted count v/s question order.[1,2,3,4]
omitted_histogram.omitted

List of the omitted count (y axis) corresponding to each item in the question order list above.

Omitted count is the number of test takers who have skipped a question.

[0,0,0,0]
not_reached_histogram.question_orderList of the question order (x axis) in a histogram plot of the unexposed count v/s question order.[1,2,3,4]
not_reached_histogram.not_reached

List of the unexposed count (y axis) corresponding to each item in the question order list above.

Unexposed count is the number of test takers who did not reach a question.

[0,0,0,0]
facility_per_question_histogram.question_orderList of the question order (x axis) in a histogram plot of the question facility v/s question order.[1,2,3,4]
facility_per_question_histogram.facilityList of the question facility (y axis) corresponding to each item in the question order list above.[1,1,1,0]
discrimination_per_question_histogram.question_orderThis is a list of the question order (x axis) in a histogram plot of the discrimination v/s question order.[1,2,3,4]
discrimination_per_question_histogram.discriminationList of the question discrimination (y axis) corresponding to each item in the question order list above.[0,0,0,0]
facility_per_question_type_histogram.question_typeThis is a list of the question types (x axis) in a histogram plot of the question facility v/s question type.["content_question_qti2_multiple_choice"]
facility_per_question_type_histogram.facilityList of the question facility (y axis) corresponding to each item in the question type list above.[0.75]
mean_score_per_question_type_histogram.question_typeThis is a list of the question types (x axis) in a histogram plot of the question mean score v/s question type.["content_question_qti2_multiple_choice"]
mean_score_per_question_type_histogram.mean_scoreList of the question mean score (y axis) corresponding to each item in the question type list above.[0.75]
facility_per_interaction_histogram.question_orderThis is a list of the question order (x axis) in a histogram plot of the interaction facility v/s interaction order.[1,2,3,4]
facility_per_interaction_histogram.interaction_order_in_questionThis is a list of the interaction order in each question (x axis) in a histogram plot of the interaction facility v/s interaction order.[1,1,1,1]
facility_per_interaction_histogram.facilityList of the interaction facility (y axis) corresponding to each item in the interaction order list above.[1,1,1,0]
discrimination_per_interaction_histogram.question_orderThis is a list of the question order (x axis) in a histogram plot of the discrimination facility v/s interaction order.[1,2,3,4]
discrimination_per_interaction_histogram.interaction_order_in_questionThis is a list of the interaction order in each question (x axis) in a histogram plot of the interaction discrimination v/s interaction order.[1,1,1,1]
discrimination_per_interaction_histogram.discriminationList of the interaction discrimination (y axis) corresponding to each item in the interaction order list above.[0,0,0,0]
row_timestamp

The time of which this record was generated. Upon conflicts the record with the latest row_timestamp will always be used.

Format is yyyy-MM-ddTHH:mm:ssZ

2025-12-04T07:42:43.783Z

 


 

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