Beginning Quantity Discrimination
Beginning Quantity Discrimination (BDQ) is a standardized, individually administered measure of early numeracy that assesses a student’s ability to discriminate between two quantities. BQD is also an indirect measure of subitizing, the ability to instantly judge the number associated with a group of items. Subitization is thought to be an important precursor to math development.
To administer BQD, the assessor presents the student with a sheet that contains a series of boxes with two patterns of dots in them and asks the student to orally name the number of dots that is the larger quantity. Since BQD assesses a student’s fluency with quantity discrimination, the measure is timed.
| Skill | Magnitude Comparison and Subitization (indirectly) |
| Administration Time | 1 minute |
| Administration Schedule |
Beginning of kindergarten to end of kindergarten |
| Score | 1 point for each correctly identified number |
| Wait Rule | If the student does not respond within 3 seconds on an item, provide the correct answer and mark a slash (/) through the number. |
| Discontinue Rule |
0 points in the first four items (the first page) |
Scoring Rules for BDQ
- Leave correct items blank. Score the student’s response as correct by leaving the item blank if the student correctly names the larger number.
- Slash incorrect items. Score the student’s response as incorrect by drawing a slash (/) through the item if the student states any number other than the correct answer, skips an item or hesitates with an answer after 3 seconds.
- Self-corrections. If the student self-corrects within 3 seconds, write “sc” over the item that had been previously slashed. Count that item as correct.