Every file format PACER accepts, with example data you can view and download. Each tool expects a specific layout — use these as starting points for your own data. Some formats are flexible: column headers become identifiers within the analysis, so you can name them anything that makes sense for your data. Others are prescribed: PACER looks for specific column names to locate the right data, and the wrong name will trigger a validation error. Each file card is labeled so you know which rule applies before you start formatting your data.
Column headers are item names. Values are numeric scores (0/1 for binary, 0–K for polytomous). An optional group column may be included anywhere for DIF analysis. Leave missing values blank or code as NA.
| Q1 | Q2 | Q3 | Q4 | Q5 | group |
|---|---|---|---|---|---|
| Item column | Item column | Item column | Item column | Item column | Optional — DIF grouping |
| 1 | 0 | 1 | 1 | 0 | Reference |
| 1 | 1 | 1 | 0 | 1 | Reference |
| 0 | 1 | 0 | 1 | 1 | Focal |
| 1 | 0 | 1 | 1 | 1 | Focal |
| 0 | 0 | 1 | 0 | 0 | Reference |
group column with at least two distinct values (e.g. Reference / Focal)Same wide-format layout as Item Analysis. Binary items use 0/1; polytomous items use integer scores 0–K. Binary and polytomous items may be mixed in the same file — PACER auto-detects: any column with a value > 1 is treated as polytomous. Leave missing responses blank or code as NA.
| ITEM01 | ITEM02 | ITEM03 | ITEM04 | POLY01 | POLY02 |
|---|---|---|---|---|---|
| Binary item | Binary item | Binary item | Binary item | Polytomous (0–3) | Polytomous (0–4) |
| 1 | 0 | 1 | 1 | 2 | 3 |
| 1 | 1 | 0 | 1 | 1 | 2 |
| 0 | 1 | 1 | 0 | 3 | 4 |
| 1 | 0 | 1 | 1 | 0 | 1 |
| 0 | 0 | 0 | 1 | 2 | — |
Scoring requires two files: item parameters and response data. If you ran calibration in PACER, both are loaded automatically — you only need to upload manually when working with external parameter estimates.
Binary items use a, b, c. Polytomous items (GRM / GPCM) use a plus threshold columns d1, d2, d3…. Leave unused cells blank. The name column may also be called itemKey, item, key, itemId, or id — PACER accepts all of these.
| columnName | model | a | b | c | d1 | d2 | d3 |
|---|---|---|---|---|---|---|---|
| Item name (or itemKey, item, key, itemId, id) | 1PL · 2PL · 3PL · GRM · GPCM | Discrimination | Difficulty | Guessing | Threshold 1 | Threshold 2 | Threshold 3 |
| ITEM01 | 2PL | 0.8794 | -0.9216 | — | — | — | — |
| ITEM02 | 3PL | 1.7345 | -0.3142 | 0.1316 | — | — | — |
| ITEM03 | GRM | 2.1200 | — | — | -1.0851 | -0.1300 | 1.4424 |
| ITEM04 | GPCM | 0.9530 | — | — | -1.9818 | 0.1647 | — |
Three required columns: testID (examinee identifier — also accepted: personId, id), key (the item's name — must match a value in columnName of the parameter file), score (0/1 for binary; integer for polytomous). Sparse data is supported.
| testID | key | score |
|---|---|---|
| Examinee ID (or personId, id) | Matches columnName value in params | 0/1 binary · 0–K poly |
| EX001 | ITEM01 | 1 |
| EX001 | ITEM02 | 0 |
| EX001 | ITEM03 | 2 |
| EX002 | ITEM01 | 1 |
| EX002 | ITEM02 | 1 |
| EX002 | ITEM04 | 1 |
key value must match a value in columnName of the parameter file — the column name is key here but the values must be identical to those in the params. Also accepted: itemKey, itemId, itemEquating requires two parameter files — the Item Bank (old scale parameters) and the New Form (new form parameters). Both files use the same column layout. Items shared between forms serve as anchors; their item_id values must match exactly across both files.
| item_id | model | a | b | c |
|---|---|---|---|---|
| Unique identifier | 1PL · 2PL · 3PL | Discrimination | Difficulty | Guessing (blank = 0) |
| ITEM001 | 2PL | 0.8794 | -0.9216 | — |
| ITEM002 | 2PL | 0.6494 | -0.5570 | — |
| ITEM003 | 3PL | 1.7345 | -0.3142 | 0.1316 |
| ITEM004 | 3PL | 1.6109 | -0.9719 | 0.1766 |
item_id values in both files — only items appearing in both are used as anchorsCDM Calibration requires two files: a binary response matrix and a Q-matrix that maps items to skills.
Wide format. Header row with item names required. Values must be 0 or 1. Item column names must correspond in order to rows of the Q-matrix.
| Q1 | Q2 | Q3 | Q4 | Q5 | Q6 |
|---|---|---|---|---|---|
| Item column | Item column | Item column | Item column | Item column | Item column |
| 1 | 0 | 1 | 1 | 0 | 1 |
| 1 | 1 | 1 | 0 | 1 | 0 |
| 0 | 1 | 0 | 1 | 1 | 1 |
| 1 | 0 | 1 | 1 | 0 | 0 |
| 0 | 0 | 1 | 0 | 1 | 1 |
One row per item, in the same order as the response matrix columns. One column per skill. A value of 1 means the item requires that skill; 0 means it does not. Column headers become skill names throughout the output.
| Skill1 | Skill2 | Skill3 |
|---|---|---|
| Skill (0 or 1) | Skill (0 or 1) | Skill (0 or 1) |
| 1 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 1 | 0 |
| 0 | 0 | 1 |
| 1 | 0 | 1 |
| 0 | 1 | 1 |
The Skill Profiler loads parameters from a saved CDM Calibration session automatically. If uploading manually, three files are needed: item parameters, a Q-matrix, and a response matrix.
Three columns: itemName (item identifier), guess (probability of correct response without required skills), slip (probability of incorrect response despite having all required skills).
| itemName | guess | slip |
|---|---|---|
| Item identifier | P(correct | no skills) | P(incorrect | all skills) |
| Q1 | 0.1824 | 0.0951 |
| Q2 | 0.2103 | 0.1240 |
| Q3 | 0.0883 | 0.1571 |
| Q4 | 0.1567 | 0.0724 |
| Q5 | 0.2291 | 0.1138 |
| Q6 | 0.1640 | 0.0873 |
The Q-matrix and response matrix use the exact same format as CDM Calibration above — same column layout, same ordering requirements.