**Table 3. Selected robustness results for the Grade 4-to-5 BB-to-AA transition (percent)**

| System | Primary 475 | Std. 475 | Cut 400 | 450→500 buffer | Both wave | Response IPW | MNAR −40 | Follow-up discordance |
| --- | ---: | ---: | ---: | ---: | ---: | ---: | ---: | ---: |
| Georgia | 16.6 | 15.9 | 26.7 | 3.9 | 17.3 | 17.2 | 15.9 | 5.9 |
| Italy | 28.2 | 21.3 | 41.9 | 6.0 | 28.8 | 28.3 | 28.0 | 7.6 |
| Jordan | 11.9 | 18.1 | 19.9 | 4.5 | 11.4 | 11.5 | 10.5 | 3.5 |
| Republic of Korea | 32.5 | 22.7 | 22.9 | 4.9 | 32.3 | 32.3 | 31.4 | 9.1 |
| Kosovo | 5.5 | 8.6 | 14.0 | 0.8 | 5.6 | 5.5 | 5.3 | 1.8 |
| Montenegro | 18.7 | 17.1 | 28.0 | 4.9 | 18.6 | 18.5 | 18.5 | 5.7 |
| North Macedonia | 10.6 | 14.1 | 18.4 | 3.0 | 10.7 | 10.6 | 10.2 | 2.9 |
| Slovenia | 34.1 | 25.6 | 47.0 | 8.0 | 34.9 | 34.1 | 32.9 | 11.1 |
| Sweden | 25.4 | 20.1 | 35.3 | 5.4 | 24.5 | 24.1 | 23.2 | 11.1 |

*Note.* Std. 475 is common-severity standardized at 475. Cut 400 and the 450→500 buffer define different denominators and events. Both wave denotes observed both-wave participants; response IPW denotes the inverse-probability-weighted response analysis. MNAR −40 is an imposed missing-not-at-random score-shift scenario. Follow-up discordance is the exploratory follow-up same-wave unequal-index classification-discordance diagnostic; its interval is JRR sampling-only conditional on five released plausible values, not an adjusted longitudinal estimate. Complete standard errors and intervals are in Additional files 1 and 2.
