IB Computer Science Internal Assessment guide

What this criterion assesses

The problem scenario described in terms of its measurable solution requirements, appropriate success criteria stated as measurable outcomes, and the choice of computational context for the solution explained. (~300 words.)

Mark band descriptors

Criterion A: Problem specification (0–4):
- 0: The response does not reach the standard described below.
- 1–2: The response outlines a problem scenario; states limited success criteria; outlines the nature of the solution in a computational context.
- 3–4: The response describes the problem scenario in terms of its measurable solution requirements; states appropriate success criteria; explains the choice of computational context for the solution.
Note: Recommended ~300 words. The success criteria must be measurable outcomes derived from the solution requirements; they anchor criteria B–E.

What this criterion assesses

A reasonable decomposition of the problem scenario (e.g. structure chart or hierarchy diagram) and a plan — a chronology covering planning, designing, developing, testing and evaluating — that addresses the success criteria. (~150 words.)

Mark band descriptors

Criterion B: Planning (0–4):
- 0: The response does not reach the standard described below.
- 1–2: The response constructs a partial decomposition of the problem scenario; constructs a plan that addresses some of the success criteria of the solution.
- 3–4: The response constructs a reasonable decomposition of the problem scenario; constructs a plan that addresses the success criteria of the solution.
Note: Recommended ~150 words. Expected: a decomposition diagram (structure chart, hierarchy diagram or similar) and a chronology (e.g. Gantt or sprint plan) covering planning, designing, developing, testing and evaluating.

What this criterion assesses

A complete system model that a third party could use to recreate the product, algorithms for the system's components that enable the product to perform, and a described testing strategy aligned with the success criteria. (~150 words excluding diagrams and algorithms.)

Mark band descriptors

Criterion C: System overview (0–6):
- 0: The response does not reach the standard described below.
- 1–2: The response outlines a limited system model; identifies algorithms for the components of the system model; identifies a testing strategy for at least one success criterion.
- 3–4: The response constructs a system model that is not complete; constructs algorithms for the components of the system model that lead to partial functionality of the product; outlines a testing strategy that aligns with at least three success criteria.
- 5–6: The response constructs a complete system model; constructs algorithms for the components of the system model that enable the product to perform; describes a testing strategy that aligns with the success criteria.
Note: Recommended ~150 words (diagrams, algorithms and tables excluded). The system model should show components, relationships, rules, algorithms and the user interface.

What this criterion assesses

The built product: a fully functional product constructed with appropriate techniques to implement the algorithms, the implementation choices evaluated, and the effectiveness of the testing strategy justified. (~1,000 words; full source code in appendices; functionality demonstrated in the video.)

Mark band descriptors

Criterion D: Development (0–12):
- 0: The response does not reach the standard described below.
- 1–3: The response constructs a product with very limited functionality; constructs a product using no appropriate techniques to implement the algorithms; states the choices made to implement the algorithms; states the testing strategy used.
- 4–6: The response constructs a product that has limited functionality; constructs a product using at least one appropriate technique to implement the algorithms; outlines the choices made to implement the algorithms; states the effectiveness of the testing strategy.
- 7–9: The response constructs a product that has partial functionality; constructs a product that uses some appropriate techniques to implement the algorithms; explains the choices made to implement the algorithms; describes the effectiveness of the testing strategy.
- 10–12: The response constructs a fully functional product; constructs a product that uses appropriate techniques to implement the algorithms; evaluates the choices made to implement the algorithms; justifies the effectiveness of the testing strategy.
Note: Recommended ~1,000 words (code excerpts, comments and diagrams excluded). Full source code goes in the appendices and functionality is evidenced in the 5-minute video; this review can only assess what the written documentation demonstrates.

What this criterion assesses

An evaluation of the extent to which each success criterion was met (fully, partially, not at all) supported by evidence, and justified improvements to the product, each tied to gaps identified in the evaluation. (~400 words.)

Mark band descriptors

Criterion E: Evaluation (0–4):
- 0: The response does not reach the standard described below.
- 1–2: The response states the extent to which the success criteria were met; describes improvements to the product.
- 3–4: The response evaluates the extent to which the success criteria were met; justifies improvements to the product.
Note: Recommended ~400 words (tables excluded). A table alone is not enough for the top band — the prose must explain how criteria were met or partially met, with evidence, and each improvement must be justified by an identified gap.