Toward Embedding-Based Psychometrics: Structural Modeling of Assessment-Item Semantics With Contextual Scores
Organizations: Faculty of Education, The University of Hong Kong
Abstract
Contextual scores represent assessment items through their similarities to reference words in an external corpus. We examine the semantic structure of scores for 40 TIMSS mathematics scored units using a partially specified two-step factor procedure. A search across factor counts identifies a persistent seven-group structure under the featured construction. Subsequent comparisons consistently favor a general dimension alongside group associations, although individual group memberships remain sensitive to some specification choices. Item examples distinguish recurring, cross-domain, sensitive, and imposed associations. Simpler and unrestricted references clarify the contribution and limits of the anchored representation: it improves on a single factor but does not achieve the lowest working Bayesian information criterion (BIC). A separate response benchmark compares three initial Q constructions and their Hull-PVAF revisions under higher-order and saturated attribute distributions. Among these diagnostic models, BIC favors the official content framework and the Akaike information criterion (AIC) favors its direct four-factor augmentation, but a matched unidimensional two-parameter logistic model has lower AIC and BIC than all twelve conditions. These findings support a conditional semantic representation while limiting direct diagnostic interpretation. We discuss learned text-assisted response calibration as a prospective application requiring a larger calibrated item bank and independent evaluation.
Figures & tables
| Feature | Contextual-score matrix | Student-response matrix |
|---|---|---|
| Row unit | Frequent-word semantic profile across 40 items | Student responses across administered items |
| Origin | Computed conditional on encoder, corpus, template, and vocabulary | Sampled behavior under the TIMSS booklet design |
| Row relation | Word profiles share corpus and encoder geometry; no i.i.d. sampling claim is made | Students are observational units under a complex booklet design; item coverage is sparse |
| Primary outputs | Semantic loadings, posterior inclusion support, and descriptive item-factor associations | Item parameters and residual dependence |
| Role here | Constructs and perturbs the text-side representation | Evaluates limited behavioral bridges only |
| Layer | Count evidence | Structural evidence | Reporting outcome |
|---|---|---|---|
| L1 | Persistent | Persistent structure with count support | |
| L2 | and is nonempty | Persistent | Persistent structure with count uncertainty |
| L3 | Count paths may be usable or unusable | All candidate counts fail the persistence rule | No persistent structure identified |
| Unclassified | Any | Persistence unresolved, or persistent with no finite count reading | Report the evidence limitation; do not relabel it L3 |
| Factor count | |||
|---|---|---|---|
| 4 | .986 | .695 | .647 |
| 5 | .451 | .342 | .322 |
| 6 | .928 | .855 | .878 |
| 7 | .900 | .926 | .924 |
| 8 | .742 | .604 | .385 |
| 9 | .589 | .325 | .384 |
| Depth | Profile | Persistent counts | /layer | ||
|---|---|---|---|---|---|
| 2 | 8, 9 | .85/one | 5, 7 | 7/L2 | 1 |
| 2 | 8, 9 | .80/two | 5, 7 | 7/L2 | 1 |
| 2 | 8, 9 | .70/three | 5 | 5/L2 | 3 |
| 4 | 7, 9 | .85/one | 4, 6, 7 | 7/L1 | 0 |
| 4 | 7, 9 | .80/two | 6, 7 | 7/L1 | 0 |
| 4 | 7, 9 | .70/three | 6, 7 | 7/L1 | 0 |
| Definition | Effective (O/B) | Oblique BIC | Bifactor BIC | BIC | Verdict |
|---|---|---|---|---|---|
| Depth 4, globally disjoint | 174/173 | 92,910.9 | 89,432.5 | 3,478.4 | Bifactor |
| Depth 4, overlap permitted | 175/173 | 92,646.2 | 90,182.8 | 2,463.3 | Bifactor |
| Depth 2, overlap permitted | 174/171 | 91,800.9 | 89,702.4 | 2,098.5 | Bifactor |
| Depth 2, globally disjoint | 174/180 | 91,800.8 | 90,094.9 | 1,705.9 | Bifactor |
| Model | Factors | Nominal/rank | Working AIC | Working BIC | Hard SRMR |
|---|---|---|---|---|---|
| One factor | 1 | 80/80 | 125,201.8 | 125,644.2 | .0712 |
| Framework PCFA | 4 | 133/133 | 103,758.2 | 104,493.7 | .0622 |
| Retained oblique | 7 | 174/174 | 91,948.7 | 92,910.9 | .0676 |
| Retained bifactor | 8 | 173/173 | 88,475.8 | 89,432.5 | .0278 |
| Unrestricted eight | 8 | 360/332 | 83,570.3 | 85,406.2 | .0574 |
| Factor | SSL share | Relative effect | Mapped | Three largest loadings | Composition or stem concentration |
|---|---|---|---|---|---|
| G | 75.8% | 1.000 | 40 | 23 (+.929), 6 (+.924), 10 (+.919) | Positive global elevation |
| S1 | 6.4% | .175 | 19 | 29 (+.607), 27 (+.569), 19 (+.442) | Algebra 11; number 7; geometry 1 |
| S2 | 3.9% | .152 | 13 | 35 (+.720), 40 (+.640), 15 (+.327) | Data 6; algebra 4; number 3 |
| S3 | 3.6% | .185 | 10 | 31 (+.717), 34 (+.661), 32 (+.270) | Geometry 4; data 3; number 3 |
| S4 | 1.3% | .056 | 11 | 11 (+.338), 6 (+.271), 5 (+.188) | Number 8; algebra 3 |
| S5 | 3.0% | .086 | 18 | 25 (+.472), 24 (+.361), 14 (+.332) | Broad/sign mixed; M042198 share = 39.9% |
| Item and task | Association | Interpretation |
|---|---|---|
| M042245: identify the equation fitting two coordinate pairs | Adopted S1 loading .607, PIP 1.000; free and selected in all four definitions | The algebra-centered group captures a recognizably algebraic task. |
| M042186: extend a subtraction pattern to a negative subtrahend | Official number domain; PCFA algebra addition .923, PIP 1.000 | Contextual scores connect an arithmetic item with algebraic pattern extension. The initial PCFA Q retains its official number membership. |
| M032047: express the sum of three consecutive integers when the middle is | Adopted S6 loading .100, PIP .662; free and selected in two of four definitions | A formally algebraic expression can have a weak, definition-sensitive secondary association. |
| M042169C: compare effects on the mean and median after increasing the largest staff count | Adopted S6 loading .615; imposed marker | Shared context and statistical content both contribute plausible interpretations. This imposed cell has no estimated PIP. |
| Comparison | Numerical result | Interpretation |
|---|---|---|
| General profiles across definitions | Centered –.9978; | Broad common dimension with some relative-profile variation |
| Matched group profiles | Minimum –.8797 across definition pairs | Less uniform group patterns |
| 237 always-free cells | 33 selected throughout; 145 never selected; 59 change status | Estimated-cell recurrence, excluding imposed markers |
| Frequency cutoff 35 | 1,330 words; minimum group | Close agreement conditional on the adopted design |
| Frequency cutoff 50 | 1,080 words; minimum group | Close agreement conditional on the adopted design |
| Dot-product scores | Minimum group ; centered G | Metric choice changes some associations |
| Construction | Attributes | Initial memberships | Hull additions/removals | Revised memberships |
|---|---|---|---|---|
| Official content framework ( , ) | 4 | 40 | 3 / 1 | 42 |
| Semantic group projection ( , ) | 7 | 93 | 0 / 2 | 91 |
| Framework-guided PCFA ( , ) | 4 | 87 | 2 / 3 | 86 |
| Panel A. CDM comparisons | |||||
|---|---|---|---|---|---|
| Q/model | Dist. | log | AIC | BIC | |
| Sat. | 95 | -30,896.98 | 61,983.96 | 62,619.30 | |
| HO | 88 | -30,933.93 | 62,043.87 | 62,632.39 | |
| Sat. | 99 | -30,873.91 | 61,945.82 | 62,607.91 | |
| HO | 92 | -30,908.08 | 62,000.16 | 62,615.43 | |
| Sat. | 417 | -30,486.56 | 61,807.13 | 64,595.93 | |
Appendix figures & tables17 assets
Supplementary material from the paper’s appendix.
Appendix
| Panel A. Item-column marginals | ||
|---|---|---|
| Data object | Skewness, median (range) | Excess kurtosis, median (range) |
| Cosine contextual scores | ||
| Dot-product contextual scores | ||
| Binary item responses | ||
| Stage | Setting |
|---|---|
| Step 1 | vbpm 0.9.0; R 4.5.1; seed 2026; maximum 10,000 iterations; convergence tolerance |
| Step-1 prior path | ; raw PIP threshold .50 |
| Candidate design | 24 specifications and 276 fits; content –14 and cognitive –14 |
| Count and persistence | 20% BIC/ELBO paths; direct minimum congruence .85/one, .80/two, and .70/three |
| Step 2 | vbpm 0.9.1; four fixed definitions; oblique and bifactor within each; BIC tie band 2 |
| Text references | vbpm 0.9.1; same prior path; 10,000 iterations per stage, with one 20,000-iteration escalation if needed; tolerance |
| Depth | Backbone | Corpus | Spec. | .85/one | .80/two | .70/three | ||
|---|---|---|---|---|---|---|---|---|
| 2 | Cogn. | E | AZ | 7 | 9 | –/L3 | –/L3 | –/L3 |
| 2 | Cogn. | E | AO | 7 | 9 | 3/L2 | 3/L2 | 3/L2 |
| 2 | Cogn. | M | AZ | 8 | 8 | 6/L2 | –/L3 | –/L3 |
| 2 | Cogn. | M | AO | 7 | 9 | 5/L2 | 3/L2 | 3/L2 |
| 2 | Cont. | E | AZ | 10 | 10 | 7/L2 | –/L3 | –/L3 |
| 2 | Cont. | E | AO | 8 | 9 | 5/L2 | –/L3 | –/L3 |
| Step | ELBO gain (%) | BIC gain (%) | Adjacent | RMSD max | Collision |
|---|---|---|---|---|---|
| 100.0 | 100.0 | .986 | .096 | No | |
| 56.3 | 56.9 | .451 | .227 | No | |
| 48.9 | 36.4 | .928 | .160 | No | |
| 29.7 | 1.6 | .900 | .181 | No | |
| 20.7 | 30.6 | .742 | .228 | No | |
| 14.7 | -17.9 | .589 | .213 | No |
| Framework and domain | Depth 2 | Depth 4 | Depth 6 |
|---|---|---|---|
| Content: algebra | 22, 28 | 20, 22, 27, 28 | 19, 20, 22, 25, 27, 28 |
| Content: data and chance | 35, 40 | 35, 36, 39, 40 | 35, 36, 37, 38, 39, 40 |
| Content: geometry | 31, 32 | 31, 32, 33, 34 | 31, 32, 33, 34 (cap) |
| Content: number | 2, 6 | 2, 4, 5, 6 | 2, 3, 4, 5, 6, 12 |
| Cognitive: applying | 7, 31 | 7, 21, 31, 39 | 7, 9, 21, 31, 33, 39 |
| Cognitive: knowing | 13, 19 | 4, 13, 19, 36 | 4, 13, 19, 30, 35, 36 |
| Definition | Backbone markers per S1–S4 | S5 markers | S6 markers | S7 markers |
|---|---|---|---|---|
| Depth-4 overlap | 4 | 9, 15, 35, 40 | 15, 36, 37, 38 | 7, 9, 13, 33 |
| Depth-4 disjoint | 4 | 9, 16, 17, 23 | 1, 15, 37, 38 | 7, 8, 13, 18 |
| Depth-2 overlap | 2 | 36, 38 | 13, 33 | 35, 40 |
| Depth-2 disjoint | 2 | 36, 38 | 13, 33 | 9, 15 |
| Off-diagonal residual summary | Hard-selected covariance | Continuous covariance |
|---|---|---|
| Root mean square | .0284 | .0150 |
| Mean absolute | .0219 | .0105 |
| Maximum absolute | .1066 | .0824 |
| Panel A. Nine-factor EFA projection | ||||
|---|---|---|---|---|
| Threshold | Memberships | Density | Unassigned | Multiple |
| 44 | .1222 | 0 | 4 | |
| Panel B. Raw-embedding cluster alignment with content | ||||
| Method | Clusters | Cramér’s | ARI | |
| -means | 4 | .5566 | .2327 | |
| -means | 8 | .8373 | .3170 | |
| No. | G | S1 | S2 | S3 | S4 | S5 | S6 | S7 |
|---|---|---|---|---|---|---|---|---|
| 1 | ||||||||
| 2 | ||||||||
| 3 | ||||||||
| 4 | ||||||||
| 5 | ||||||||
| 6 |
| No. | G | S1 | S2 | S3 | S4 | S5 | S6 | S7 |
|---|---|---|---|---|---|---|---|---|
| 1 | ||||||||
| 2 | ||||||||
| 3 | ||||||||
| 4 | ||||||||
| 5 | ||||||||
| 6 |
| No. | Item | Alg. | Data | Geom. | Num. | No. | Item | Alg. | Data | Geom. | Num. |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | M032064 | 0 | 21 | M042086 | 0 | 0 | |||||
| 2 | M032094 | 0 | 22 | M042103 | 0 | 0 | 0 | ||||
| 3 | M032166 | 0 | 23 | M042198A | 0 | ||||||
| 4 | M032626 | 24 | M042198B | 0 | |||||||
| 5 | M032725 | 0 | 0 | 0 | 25 | M042198C | 0 | ||||
| 6 | M042032 | 0 | 0 | 0 | 26 | M042226 | 0 | 0 |
| Revision | Item | Attribute | Edit |
|---|---|---|---|
| M032132 | algebra | Addition | |
| M052216 | data and chance | Addition | |
| M042198A | data and chance | Addition | |
| M032132 | data and chance | Removal | |
| M052214 | S4 | Removal | |
| M032295 | S6 | Removal |
| Definition | Reduced groups | Reduced zero rows | Reduced identity witness | Full zero rows | Full identity witness | Joint pass |
|---|---|---|---|---|---|---|
| Depth-4 disjoint | 5 | 2 | No | 0 | No | No |
| Depth-4 overlap | 5 | 2 | Yes | 0 | No | No |
| Depth-2 overlap | 5 | 4 | No | 0 | No | No |
| Depth-2 disjoint | 6 | 0 | No | 0 | No | No |
| Panel A. Diagnostics for the twelve CDM conditions | ||||
|---|---|---|---|---|
| Q | Dist. | Boundary items/cells | Nonmonotone items/decreases | Pair RMS |
| Sat. | 1/1 | 0/0 | .0201 | |
| HO | 1/1 | 0/0 | .0206 | |
| Sat. | 3/3 | 2/3 | .0198 | |
| HO | 3/3 | 2/2 | .0204 | |
| Sat. | 22/112 | 23/155 | .0190 | |
| Panel A. Four text-based projections | ||||
|---|---|---|---|---|
| Definition | log | AIC | BIC | |
| Depth-4 disjoint | 297 | -30,872.48 | 62,338.96 | 64,325.23 |
| Depth-4 overlap | 263 | -30,860.22 | 62,246.43 | 64,005.32 |
| Depth-2 overlap, escalated | 293 | -30,891.72 | 62,369.44 | 64,328.96 |
| Depth-2 disjoint | 325 | -30,792.76 | 62,235.52 | 64,409.05 |
| Panel B. Density-matched placement null | ||||
| Item set | Item pairs | Pearson | Spearman | Null-calibrated |
|---|---|---|---|---|
| All 40 items | 316 | .035 | .031 | 1.93 |
| Exclude M042169 | 262 | .041 | .029 | 2.63 |
| Exclude M042198 | 262 | .079 | .074 | 2.46 |
| Exclude both bundles | 217 | .093 | .071 | 2.99 |
| Representation | Target | Mean (SD) | Range | Positive repeats | Leave-one-group-out |
|---|---|---|---|---|---|
| Contextual scores | 2PL | .025 (.032) | -.074 to .058 | 17/20 | .030 |
| Raw item embedding | 2PL | -.094 (.039) | -.195 to -.021 | 0/20 | -.076 |
| Contextual scores | 2PL | -.094 (.054) | -.255 to -.026 | 0/20 | -.071 |
| Raw item embedding | 2PL | -.141 (.061) | -.261 to -.059 | 0/20 | -.170 |