Organizations: Homi Bhabha Centre for Science Education–TIFR, Mumbai, India · Lawrence Livermore National Laboratory, Livermore, CA, USA · University of California, Berkeley, CA, USA · Indian Institute of Technology, Guwahati, India · Centre for Excellence in Basic Sciences, Mumbai, India
Multimodal AI can read handwritten physics solutions, but high-stakes grading requires agreement with official scores and outcomes. This study evaluated GPT-5.5-based grading on 10364 scanned pages from 520 handwritten submissions by 416 unique candidates or students across three assessments: a national Physics Olympiad theory examination, the final Olympiad selection camp with theory and experiment components, and a university quantum-mechanics examination. Each submission was graded twice by AI using the official rubrics. The second round used revised page-by-page and evidence-location instructions developed after first-round disagreement analysis. During grading, AI did not see official human marks or AI--human comparisons. Total-score correlations with official marks were high (0.91--0.97). For the final Olympiad selection, AI recovered the same five-student team as official grading. The second round improved aggregate question-part agreement, especially where first-round disagreements were larger. The main difficulty remained exact partial-credit grading, especially in experimental work. Reliable AI grading therefore depends on detailed rubrics and should be used as a second reader or audit tool under examiner control.
Figures & tables
Dataset
Candidates/ students
Exam submissions
Exam components
Scanned pages
Main role
OE1
350
350
1
5600
Top-cohort identification
OE2
26
130
5
4164
Final team selection
QM
40
40
1
600
University class grade
Total
416
520
7
10 364
–
Table 1: Datasets used in the study. An exam component means one separately graded OE2 theory or experiment test section. An exam submission means one student’s answer booklet for one component. OE1 and QM each had one component per student, while OE2 candidates completed five components.
Model
Effort
Exams/runs included
GPT-5.5 Thinking
High
Main RI/RII grading: OE1, OE2, QM
GPT-5.5 Pro
Standard
OE2 full comparison and outcome check
GPT-5.5 Pro
Extended
OE2 pilot involving selected submissions
Table 2: AI models and effort settings used in the study.
Quantity
What it measures
Purpose
r
Pearson correlation between human and AI scores
Score tracking
ρ
Spearman rank correlation
Rank-order agreement
D
Mean of AI minus human scores. Positive values mean AI awarded more
Direction of over- or under-awarding
MAD
Mean absolute difference between AI and human scores
Size of the grading difference
Top- k overlap
Fraction of human top- k submissions also in the AI top- k
Top-group and team-selection checks
d=∣AI−Human∣
Raw point difference for one official question part
Difference bands for individual question parts
Table 3: Analysis parameters used in the study. Unless raw marks are explicitly stated, D and MAD are reported as percentages of the relevant maximum possible score.
Figure 1: AI versus human total scores in RI and RII, expressed as percentages of the assessment maximum. Each point represents one student. The diagonal line is perfect agreement. Blue points show RI and green points show RII. r , ρ , D , and MAD are shown inside each panel.
Figure 2: Residual total-score plots pooled across OE1, OE2 theory, OE2 experiment, and QM. The vertical axis is AI minus human total score, expressed as a percentage of the assessment maximum. Blue circles show RI and green squares show RII. The fitted line is a least-squares visual guide, and the horizontal zero line is perfect agreement. The figure mainly shows the direction and spread of AI–human differences: RI is more often positive, while RII is less shifted upward. The fitted slopes should be read cautiously because the human score is part of the plotted difference.
Figure 3: Outcome agreement. The OE1 and OE2 panels show the percentage of human top- k submissions or students also present in the AI top- k group; blue circles show RI and green squares show RII. The QM panel shows RII course-grade agreement across the nine released grade categories. Green bubbles show exact grade matches and orange bubbles show different grade pairs. The number inside each bubble is the number of students; AS is the highest grade.
d=0
0<d≤0.5
0.5<d≤1
d>1
Set
Question parts
RI
RII
RI
RII
RI
RII
RI
RII
OE1
4200
61
71
15
12
9
9
15
8
OE2 theory
1482
70
75
13
13
9
6
8
6
OE2 experiment
416
45
56
21
17
9
13
25
14
QM
960
63
69
21
18
8
9
8
4
All official question parts
7058
63
70
16
14
9
9
13
7
Table 4: Agreement between AI and human scores for individual question parts. Here d=∣AI−Human∣ in raw points. Values are rounded percentages. Bands sum to 100% before rounding.
Figure 4: AI behavior by official human score group. Each bar shows the distribution of AI scores within question parts where the official human score was zero, partial credit, or full credit. The partial-credit parts contain 40% of the available points.
Figure 5: Example of AI using the full working to interpret a summary-box transcription error. (a) The transferred expression in the summary answer box is off by a factor of two. (b) The detailed working of the same submission contains the correct self-energy factor and final expression. The AI comment stated: “ The summary box misses a factor, but the working sheet correctly derives Q02/(8πϵ0)(1/R0−1/R) . ” This matched the official full-credit mark.
Figure 6: Examples of visual reasoning in AI grading. (a) Correct reference shapes from the solution. (b) Full-credit example where the relevant sketches were outside the designated answer box. AI found them on later pages and commented: “ Detailed sketches show the required below-critical, critical, and above-critical effective-potential shapes with the expected qualitative behavior. ” (c) Limited-credit example where AI awarded the endpoint behavior specified in the rubric but withheld credit for the missing double-well and critical-transition shapes. The AI comment stated: “ Provides some qualitative potential curves and endpoint behavior, but the subcritical double-well and critical transition are not represented correctly. ”
Figure 7: Examples from masked OE2 experimental submissions. Panels (a) and (b) belong to the same data-table and graph-analysis task, and the AI and official scores agreed on both marking components. AI comments for these two components were: “ The transformed 1/a+1/b values are tabulated for all n values and the linearization is written ” and “ Graph is present with plotted points, best-fit and limiting lines, and slope calculations for the equivalent 1/a+1/b plot. ” Panel (c) shows a partial-credit graph. Both graders awarded partial credit. AI comment for this component was: “ Five points are plotted on an R -versus- h graph, but no usable best-fit line, slope or uncertainty construction is shown. ”
Question type
Description
Conceptual written reasoning
Written physical explanation, evaluation of an answer choice, interpretation, or validity check.
Figure-diagram
Circuits, free-body diagrams, qualitative sketches, ray diagrams, or graph shapes where the visual structure is the answer.
Numerical
Calculation or substitution where the quantity being assessed is primarily a value, probability, time, energy, or angle.
Derivation
Symbolic proof, formula derivation, operator derivation, or multi-step algebraic reasoning.
Figure-data
Experimental measurements, data tables, plotted data, graph fitting, slope extraction, uncertainty, or data-based inference.
Table 5: Question-type labels used across the three assessments.
Figure 8: MAD by question type in RI and RII for the 7058 official question parts. MAD% is the mean absolute difference as a percentage of the maximum possible score for each part.
Question type
N
DI
DII
MAD I
MAD II
rI
rII
Conceptual written reasoning
706
+13.3
+4.3
16.6
10.7
0.83
0.89
Figure-diagram
1082
+3.8
+2.5
10.6
7.7
0.84
0.89
Numerical
1978
+4.7
+0.7
11.1
7.6
0.85
0.88
Derivation
2876
+4.8
+2.3
11.4
9.1
0.88
0.91
Figure-data
416
+3.3
+4.4
9.3
6.6
0.92
0.96
Table 6: Question-type metrics for official question parts. N is the number of question-part comparisons. D and MAD are percentages of the maximum possible score for each part.
Source
Description
Awarding credit too easily
AI sometimes awarded partial credit to work to which human examiners assigned zero points, especially when the answer contained plausible symbols, text, tables, or diagram features.
Over-valuing the final answer
A correct-looking final answer sometimes received too much credit even when the reasoning had serious errors.
Treatment of carried-forward errors
AI could recognize an earlier error but sometimes applied carried-forward-error rules differently from the human examiner.
Missing a required diagram feature
AI often read the diagram but could miss a specific feature required by the rubric, such as relative placement, curvature, scale, or a required label.
Experimental evidence chain
AI often identified tables, graphs, and calculations, but disagreements arose when the score depended on whether the data, fit, uncertainty, and conclusion supported each other.
Permitted scoring increments
In a few cases, AI awarded increments smaller than the intended scoring resolution. This should be stated clearly in the prompt.
Table 7: Recurring sources of disagreement between AI and official scores. These summarize patterns seen in reviewed cases; individual score differences are interpreted against the official scoring.
Target
Points
Responses
Main issue clarified
QM Q3b
3
40
Grover diagram and operator conditions
OE1 Q2
8
72
A thermodynamic reasoning based question
OE2 T2 Q1(f)
4
26
T – S graph shape, labels, and curvature
Table 8: Focused refinement targets selected after reviewing RI disagreements.
Figure 9: Refinement of the rubric for the OE2 question. (a) The intended T – S cycle from the solution. (b) Student sketch with labels and arrows but with the wrong curvature. In RI, AI marked this as a correct shape. The refined rubric emphasized the physical conditions of the cycle, with less reliance on labels and arrows alone.
Figure 10: Grover-rotation example from the QM exam. (a) Reference rotation diagram redrawn from the official solution. (b) Student response. In RII, the AI identified that the circuit-style sketch was not the required rotation diagram.
RI
RII
Rubric
Correct diagram with all symbols explained: 1 point. Detailed mathematical description of the Grover operator: 2 points. Determine an appropriate point allocation when the response is incomplete.
0.5 points for axes labeled as ∣x0⟩ and ∣x0⊥⟩ . 0.5 for showing rotation by 2θ under G . 0.5 for defining ∣x0⊥⟩ . 0.5 for the action of O . 1 point for the action of G=DO .
Comment by AI
Awarded 2/3. Correctly describes Grover as oracle plus diffusion and notes the oracle phase flip, with a supporting circuit-style diagram. Deducted 1 because the diffusion/reflection and amplitude-rotation geometry are not fully explained. Method partly follows the official scheme.
Awarded 0.5/3. Gives a qualitative oracle/diffusion description and a circuit-like oracle sketch, but not the required two-dimensional rotation diagram or mathematical action of O and G on cos(α)∣x0⊥⟩+sin(α)∣x0⟩ .
Table 9: RI and RII rubric/comment comparison for the Grover example in Fig. 10 .
Figure 11: AI-minus-human score distributions for two focused refinement examples, shown as percentages of submissions. The horizontal axis gives the difference between AI and human scores. The Round I bars show the original scores, and the Refined bars show scores from the question-specific refinement run.
Figure 12: Confidence flags in RII grading. Medium- and low-confidence question parts have larger differences from official scores, so confidence helps identify parts for human review.
Department of Psychology, University of Notre Dame, Notre Dame, IN, 46556, USA · Notre Dame Learning, University of Notre Dame, Notre Dame, IN, 46556, USA