Arithmetic Subtraction - 2025

1. Probe description

  • In Term 1 (BOY), students answered by dragging and dropping the correct number (0–13) into the answer box.

  • Because response times were slow at BOY, two new formats were introduced in Term 3 (MOY) and Term 4 (EOY): multiple choice and tap-tap.

  • Roughly half of the students who participated in Term 3/4 did multiple choice and the other half did tap-tap (BUT was incorrectly labelled as drag and drop / D&D).

Term 1 example - drag and drop

Term 3 / Term 4 example - multiple choice

Term 3 / Term 4 example - tap-tap

Table 1

Download Year 1 student data (wide format)

2. Overview of test results

Table 2
Term Test name Test ID Students Median items attempted Median accuracy (%)* Median correct / min
1 Subtraction drag and drop ASDD_2025 2313 5/30 80.0 4.14
3 Subtraction multiple choice 2025 new ASDD_2025_NEW 784 7/30 88.9 6.67
3 Subtraction drag and drop ASDD_2025 490 5/30 93.1 5.22
4 Subtraction MC (MOY) ASMC_MOY 1063 9/30 91.7 8.57
* Accuracy is calculated after removing non-attempted items.

3. Accuracy distribution shows some ceiling effect across iterations

4. Response time distribution

Note “T3 Sub. D&D” is actually tap-tap, not drag n’ drop.

Warning: Removed 219 rows containing non-finite outside the scale range
(`stat_ydensity()`).
Warning: Removed 219 rows containing non-finite outside the scale range
(`stat_boxplot()`).

5. Fluency shows a wider spread of student ability

Term 1 Drag n’ Drop vs Term 3 Tap-tap vs Term 3 Multiple Choice

Note Term 3 tap-tap is labelled as D&D

Wide divergence in fluency between bottom quartile vs. the rest

6. Item statistics

NoteItem discrimination

Item discrimination (point-biserial) measures how well an item separates higher-ability from lower-ability students. Values above ~0.3 are typically “good”, below ~0.2 “weak”. In timed tests, late items can look artificially strong because only fast/able students reach them.

Correct response time (sec)
Question ID Question Flag No. response % Correct Median RT 95th RT Item discrim.
Term 1 – Subtraction drag and drop (ASDD_2025)
ASDD_001 5-1 = A1 2243 82.7 8.0 24.00 0.33
ASDD_002 3-2 = D1 2172 70.2 9.0 23.00 0.41
ASDD_003 6-4 = C 1920 63.4 12.0 27.00 0.42
ASDD_004 5-5 = D0 1683 60.4 7.0 17.00 0.47
ASDD_005 5-2 = M5 1297 77.6 7.0 16.00 0.53
ASDD_006 10-6 = M10 851 73.1 8.0 16.00 0.53
ASDD_007 4-3 = D1 558 75.8 6.0 11.00 0.60
ASDD_008 6-3 = D 376 74.7 5.0 9.00 0.68
ASDD_009 2-0 = D0 278 72.7 5.0 8.00 0.53
ASDD_010 7-3 = C 151 71.5 6.0 13.00 0.67
ASDD_011 2-1 = A1 115 72.2 3.0 6.90 0.82
ASDD_012 5-2 = M5 79 68.4 3.0 6.00 0.85
ASDD_013 8-6 = C 54 55.6 4.0 7.00 0.85
ASDD_014 3-3 = D0 41 53.7 3.0 5.90 0.81
ASDD_015 5-4 = D1 28 50.0 2.5 3.00 0.98
ASDD_016 10-7 = M10 20 45.0 4.0 13.80 0.84
ASDD_017 3-2 = D1 12 41.7 3.0 4.60 NA
ASDD_018 8-4 = D 9 33.3 3.0 4.80 NA
ASDD_019 4-0 = D0 8 25.0 2.0 2.00 NA
ASDD_020 6-3 = D 8 37.5 2.0 2.90 NA
ASDD_021 4-1 = A1 4 25.0 2.0 2.00 NA
ASDD_022 6-2 = C 2 0.0 NA NA NA
ASDD_023 7-5 = C 2 0.0 NA NA NA
ASDD_024 4-4 = D0 2 0.0 NA NA NA
ASDD_025 5-3 = M5 2 0.0 NA NA NA
ASDD_026 10-4 = M10 2 50.0 8.0 8.00 NA
ASDD_027 4-2 = D 1 100.0 5.0 5.00 NA
ASDD_028 10-5 = D 1 100.0 9.0 9.00 NA
ASDD_029 3-0 = D0 1 0.0 NA NA NA
Term 3 – Subtraction drag and drop (ASDD_2025)
ASDD_001 5-1 = A1 422 82.9 8.0 22.00 0.32
ASDD_002 3-2 = D1 405 78.0 8.0 20.25 0.31
ASDD_003 6-4 = C 391 71.6 11.0 26.05 0.36
ASDD_004 5-5 = D0 356 71.3 6.0 13.00 0.40
ASDD_005 5-2 = M5 301 84.1 7.0 17.00 0.40
ASDD_006 10-6 = M10 206 85.4 7.0 16.25 0.32
ASDD_007 4-3 = D1 153 87.6 5.0 11.00 0.45
ASDD_008 6-3 = D 111 83.8 5.0 9.00 0.31
ASDD_009 2-0 = D0 85 88.2 4.0 7.30 0.18
ASDD_010 7-3 = C 48 87.5 5.0 14.00 0.49
ASDD_011 2-1 = A1 35 88.6 3.0 7.50 0.56
ASDD_012 5-2 = M5 25 96.0 3.0 4.00 0.51
ASDD_013 8-6 = C 15 86.7 4.0 7.40 NA
ASDD_014 3-3 = D0 14 85.7 3.5 4.90 NA
ASDD_015 5-4 = D1 6 83.3 3.0 4.60 NA
ASDD_016 10-7 = M10 6 66.7 2.0 2.85 NA
ASDD_017 3-2 = D1 2 50.0 2.0 2.00 NA
ASDD_018 8-4 = D 1 100.0 2.0 2.00 NA
ASDD_019 4-0 = D0 3 100.0 4.0 7.60 NA
ASDD_020 6-3 = D 1 100.0 2.0 2.00 NA
ASDD_021 4-1 = A1 2 100.0 3.0 3.90 NA
ASDD_022 6-2 = C 1 100.0 2.0 2.00 NA
ASDD_024 4-4 = D0 1 100.0 7.0 7.00 NA
ASDD_027 4-2 = D 1 100.0 6.0 6.00 NA
Term 3 – Subtraction multiple choice 2025 new (ASDD_2025_NEW)
ASMC_001 5-1 = A1 768 80.6 5.0 16.10 0.33
ASMC_002 3-2 = D1 745 78.5 6.0 15.80 0.32
ASMC_003 6-4 = C 720 75.6 9.0 25.00 0.34
ASMC_004 5-5 = D0 717 69.9 4.0 11.00 0.40
ASMC_005 5-2 = M5 630 85.2 6.0 14.00 0.41
ASMC_006 10-6 = M10 532 79.1 6.0 16.00 0.32
ASMC_007 4-3 = D1 435 82.3 6.0 14.15 0.36
ASMC_008 6-3 = D 341 84.5 4.0 10.00 0.39
ASMC_009 2-0 = D0 298 84.2 3.0 7.00 0.15
ASMC_010 7-3 = C 201 79.6 5.0 11.05 0.38
ASMC_011 2-1 = A1 151 75.5 3.0 6.00 0.58
ASMC_012 5-2 = M5 115 77.4 4.0 7.60 0.58
ASMC_013 8-6 = C 81 75.3 4.0 7.00 0.40
ASMC_014 3-3 = D0 64 68.8 2.0 6.00 0.53
ASMC_015 5-4 = D1 53 71.7 3.0 6.15 0.55
ASMC_016 10-7 = M10 36 58.3 2.0 6.00 0.80
ASMC_017 3-2 = D1 28 64.3 2.0 6.35 0.44
ASMC_018 8-4 = D 24 62.5 2.0 3.60 0.68
ASMC_019 4-0 = D0 19 57.9 3.0 6.00 NA
ASMC_020 6-3 = D 17 47.1 2.0 3.00 NA
ASMC_021 4-1 = A1 13 76.9 2.0 3.00 NA
ASMC_022 6-2 = C 13 53.8 1.0 2.70 NA
ASMC_023 7-5 = C 12 8.3 3.0 3.00 NA
ASMC_024 4-4 = D0 9 33.3 2.0 2.90 NA
ASMC_025 5-3 = M5 10 20.0 3.5 4.85 NA
ASMC_026 10-4 = M10 10 50.0 1.0 3.80 NA
ASMC_027 4-2 = D 10 40.0 1.0 1.85 NA
ASMC_028 10-5 = D 8 0.0 NA NA NA
ASMC_029 3-0 = D0 4 25.0 4.0 4.00 NA
ASMC_030 9-5 = C 4 75.0 1.0 1.90 NA
Term 4 – Subtraction MC (MOY) (ASMC_MOY)
ASMC_001-copy 5-1 = A1 1034 83.8 4.0 13.00 0.30
ASMC_002-copy 3-2 = D1 1020 83.6 5.0 15.00 0.28
ASMC_003-copy 6-4 = C 998 79.3 7.0 21.00 0.33
ASMC_004-copy 5-5 = D0 990 80.2 3.0 9.00 0.37
ASMC_005-copy 5-2 = M5 938 88.3 5.0 13.00 0.31
ASMC_006-copy 10-6 = M10 847 82.9 5.0 14.00 0.28
ASMC_007-copy 4-3 = D1 754 84.1 5.0 11.00 0.24
ASMC_008-copy 6-3 = D 638 84.0 4.0 10.00 0.33
ASMC_009-copy 2-0 = D0 567 82.9 3.0 8.00 0.24
ASMC_010-copy 7-3 = C 431 80.3 5.0 11.00 0.31
ASMC_011-copy 2-1 = A1 370 83.2 3.0 7.00 0.44
ASMC_012-copy 5-2 = M5 291 81.8 3.0 7.00 0.57
ASMC_013-copy 8-6 = C 214 80.4 3.0 7.45 0.48
ASMC_014-copy 3-3 = D0 176 83.0 2.0 4.00 0.60
ASMC_015-copy 5-4 = D1 134 76.9 2.0 5.90 0.65
ASMC_016-copy 10-7 = M10 110 75.5 2.0 5.00 0.66
ASMC_017-copy 3-2 = D1 90 76.7 2.0 4.00 0.71
ASMC_018-copy 8-4 = D 73 71.2 2.0 4.00 0.49
ASMC_019-copy 4-0 = D0 60 61.7 3.0 5.40 0.54
ASMC_020-copy 6-3 = D 46 58.7 2.0 3.00 0.80
ASMC_021-copy 4-1 = A1 35 71.4 2.0 3.00 0.47
ASMC_022-copy 6-2 = C 29 41.4 2.0 3.45 0.74
ASMC_023-copy 7-5 = C 26 38.5 2.0 3.00 0.68
ASMC_024-copy 4-4 = D0 21 52.4 2.0 5.00 0.39
ASMC_025-copy 5-3 = M5 20 55.0 1.0 2.00 0.66
ASMC_026-copy 10-4 = M10 16 68.8 1.0 1.50 NA
ASMC_027-copy 4-2 = D 18 38.9 2.0 8.30 NA
ASMC_028-copy 10-5 = D 13 15.4 1.0 1.00 NA
ASMC_029-copy 3-0 = D0 11 27.3 1.0 1.00 NA
ASMC_030-copy 9-5 = C 11 72.7 1.0 2.30 NA
Flag Question group
A1 Subtrahend Is 1
C Common
D Double
D0 Subtrahend Or Difference Is 0
D1 Difference Is 1
M10 Minuend Is Ten
M5 Minuend Is Five

7. Item correct response time

ASDD_2025 (T1)

ASDD_2025 (T3)

ASDD_2025_NEW (T3)

ASMC_MOY (T4)

8. Question group performance

Correct response time (sec)
Question group Avg items attempted No. response % Correct Median RT 95th RT
Term 1 – Subtraction drag and drop (ASDD_2025)
Common 1.1/6 2129 63.6 11 26.00
Difference Is 1 1.3/4 2770 71.0 8 21.00
Double 1/5 395 73.2 5 9.00
Minuend Is Five 1.1/3 1378 76.9 7 16.00
Minuend Is Ten 1/3 873 72.4 8 16.00
Subtrahend Is 1 1.1/3 2362 82.0 8 24.00
Subtrahend Or Difference Is 0 1.2/6 2013 61.7 6 16.00
Term 3 – Subtraction drag and drop (ASDD_2025)
Common 1.2/6 455 73.8 10 26.00
Difference Is 1 1.3/4 566 80.6 7 18.00
Double 1/5 114 84.2 5 9.00
Minuend Is Five 1.1/3 326 85.0 6 17.00
Minuend Is Ten 1/3 212 84.9 7 16.05
Subtrahend Is 1 1.1/3 459 83.4 7 21.90
Subtrahend Or Difference Is 0 1.3/6 459 75.2 5 12.00
Term 3 – Subtraction multiple choice 2025 new (ASDD_2025_NEW)
Common 1.4/6 1031 75.3 7 23.00
Difference Is 1 1.7/4 1261 79.2 6 15.00
Double 1.2/5 400 78.8 4 10.00
Minuend Is Five 1.2/3 755 83.2 5 14.00
Minuend Is Ten 1.1/3 578 77.3 6 16.00
Subtrahend Is 1 1.2/3 932 79.7 5 15.00
Subtrahend Or Difference Is 0 1.5/6 1111 73.0 4 10.00
Term 4 – Subtraction MC (MOY) (ASMC_MOY)
Common 1.7/6 1709 78.3 6 18.00
Difference Is 1 1.9/4 1998 83.0 5 13.00
Double 1.2/5 788 79.2 4 10.00
Minuend Is Five 1.3/3 1249 86.2 4 12.00
Minuend Is Ten 1.1/3 973 81.8 5 14.00
Subtrahend Is 1 1.4/3 1439 83.4 4 12.00
Subtrahend Or Difference Is 0 1.8/6 1825 80.1 3 8.00