6.7 Adaptive Testing with the CBA ItemBuilder
6.7.1 Adaptive Testing within CBA ItemBuilder Tasks
Simple forms of adaptivity, e.g. multi-stage tests with routing based on observed scores, can be implemented directly in the CBA ItemBuilder. For this purpose, within a task (i.e. also within a CBA ItemBuilder project) the selection of pages on which items are displayed can be controlled, for example, via the finite state machine.
Inspired by the number sequence test as used in the National Cohort (see Schmiedek et al. 2022), the item in Figure 6.37 illustrates a simple multi-stage test with 8 items.
Each person should be shown only a selection of items. For this purpose, two items are administered in a first stage (A). Based on the number of correct answers in stage A (0 items correct –> B0, 1 item correct –> B1, 2 items correct –> B2), a suitable second stage is then administered. The test is implemented with the CBA ItemBuilder in such a way that it can be operated without keyboard exclusively with buttons, which can be operated by mouse or touch screen. The routing is completely implemented in the Finite State Machine, as is the scoring of the input.
The number series used here in the example do not correspond to the instrument used in NAKO but are example number series as summarized in the following table:72
| Stage | Item | Number Series | Corret Response |
|---|---|---|---|
| A | 1 | 5, 6, 9, 14, 21, __ | 30 (+1,+3,+5,+7,+9; The series consists of a pattern of addition of consecutive odd numbers.) |
| 2 | 1, 3, 9, 27, __ , 243 | 81 (\(*3\), \(*3\), \(*3\), \(*3\), \(*3\); Next number of this series is multiplication of 3 with previous one. ) | |
| B1 | 3 | 1, 3, 6, 11, 18, __ | 29 (+2,+3,+5,+7,+11; The series consists of a pattern of addition of prime numbers.) |
| 4 | 1, 2, 6, 15, 31, __ | 56 (\(+1^2\),\(+2^2\),\(+3^2\), \(+4^2\); The series is based on addition of squares of consecutive natural numbers.) | |
| B2 | 5 | 32, 19, 8, __ | 1 (-13,-11,-7; The series consists of a pattern of subtraction of prime numbers.) |
| 6 | 225, 100, 36, 9, 1, __ | 0 (\(-5^3\), \(-4^3\), \(-3^3\), \(-2^3\), \(-1^3\); The series is based on subtraction of cubes of consecutive natural numbers.) | |
| B3 | 7 | 1296, 648, 216, 108, __, 18, 6, 3 | 35 (\(/2\), \(/3\), \(/2\), \(/3\), \(/2\), \(/3\), \(/2\); The terms are divided by 2 and 3 alternately.) |
| 8 | 71, 55, 46, 42, __ | 41 (\(-4^2\),\(-3^2\),\(-2^2\), \(-1^2\); The series is based on addition of squares of consecutive natural numbers.) |
6.7.2 Adaptive Testing across CBA ItemBuilder Tasks
Adaptivity across CBA ItemBuilder tasks must be supported by the deployment software. The R package ShinyItemBuilder provides a simple example to implement an adaptive test using CBA ItemBuilder tasks and R/Shiny (see 7.3.3).