Skip to contents

This is a small data set of multiplication item responses. This data contains responses to 4 items from 142 respondents, which ask respondents to complete an integer multiplication problem.





mdm_data is a tibble containing responses to multiplication items, as described in MacReady & Dayton (1977). There are 142 rows and 5 variables.

  • respondent: Respondent identifier

  • mdm1-mdm4: Dichotomous item responses to the 4 multiplication items

mdm_qmatrix is a tibble that identifies which skills are measured by each MDM item. This MDM data contains 4 items, all of which measure the skill of multiplication. The mdm_qmatrix correspondingly is made up of 4 rows and 2 variables.

  • item: Item identifier, corresponds to mdm1-mdm4 in mdm_data

  • multiplication: Dichotomous indicator for whether or not the multiplication skill is measured by each item. A value of 1 indicates the skill is measured by the item and a value of 0 indicates the skill is not measured by the item.


MacReady, G. B., & Dayton, C. M. (1977). The use of probabilistic models in the assessment of mastery. Journal of Educational Statistics, 2(2), 99-120. doi:10.2307/1164802