Objective Response Item Analysis

How to use Objective Response Item Analysis

Enter one option alphabet, an answer key and equal-length response strings. Choose whether omissions score zero or exclude incomplete records. Inspect each item's difficulty and its relation to the rest of the test, with exact integer moment witnesses and explicit constant-score states.

1. Use the example as the schema; replace its labels and entered model assumptions.
2. Enter one option alphabet, an answer key and equal-length response strings. Choose whether omissions score zero or exclude incomplete records. Inspect each item's difficulty and its relation to the rest of the test, with exact integer moment witnesses and explicit constant-score states.
3. Calculate, inspect the complete witnesses and limitations, then copy or download the JSON report.

Good to know

• At most 100 items, 200 uniquely labeled response records and 2–10 distinct uppercase ASCII options. The dot marks an omission. No normalization, lowercase conversion, partial credit, multiple correct answers or differing test forms. The global 30,000-character JSON limit also applies to labels and responses together.
• This is a descriptive classroom response audit, not a student ranking, item-validity certification, reliability estimate or item-response model. Corrected correlations use an approximate square root after exact integer moments. Constant items, constant rest totals or fewer than two included records produce null with a reason. No automatic good/bad thresholds are imposed.
• Local calculation with no upload, input persistence or outside lookup. Model JSON is limited to 30,000 characters and 10,000 values. Decimal quantities are strings with up to six places; count fields use plain JSON integers. Exact fractions are capped at 8,192 bits. The complete JSON output is limited to 1,000,000 characters; approximate numbers preserve their stored values. Unsupported states fail explicitly.