TABLE 4.
Item difficulties of link items from the 1PL Model.
| Domain | Item group | #Items | 2000 PBA | 2003 PBA | 2006 PBA | 2009 PBA | 2012 PBA | 2015 CBA | 2014 PBA vs. CBA |
| Science | S2A | 52 | − | − | −0.40 | −0.41 | −0.49 | −0.34 | −0.24 |
| S2B | 25 | − | − | −0.29 | − | − | −0.13 | −0.23 | |
| Mathematics | M1A | 31 | − | 0.01 | −0.11 | −0.14 | −0.18 | −0.07 | −0.10 |
| M1B | 35 | − | − | − | − | −0.08 | 0.17 | −0.25 | |
| Reading | R1A | 24 | −0.34 | −0.32 | −0.41 | −0.62 | − | −0.53 | −0.34 |
| R1B | 11 | −0.97 | − | − | −1.09 | − | −1.10 | −0.37 | |
| R2A | 39 | − | − | − | −0.57 | −0.66 | −0.56 | −0.07 | |
| R2B | 8 | − | − | − | 0.00 | − | −0.18 | 0.12 |
Item group = Label for subset of link items that were used in different PISA studies; #Items = Number of corresponding items in an item group; 2014 PBA vs. CBA = Difference between item difficulties in PBA and CBA modes in the field test study for PISA 2015, conducted in 2014: Negative values in the column furthest the right indicate that items are easier in the PBA mode.