Computer model — data, rules, formulae
Software representing a real-life situation using data, rules and formulae. Its defining feature is the "what-if" scenario: change ONE input variable and the model recalculates the predicted outcome, with nothing real built or risked. Five named contexts — personal finance, bridge and building design, flood-water management, traffic management, weather forecasting — each with its own what-if variable (interest rate, wind speed, rainfall, light timing, air pressure).
Advantages over the real thing or a human
The syllabus compares modelling "rather than humans" — a person building and testing the real thing, or calculating by hand. Safer: a bridge design can be run to simulated failure with no risk to life. Cheaper: a failed test costs computer time, not materials. Faster: many what-if values can be tried in minutes, not months. Repeatable: the same scenario can be re-run with one variable changed to isolate its effect — very hard to do in a real physical test.
Limits — only as good as its data and rules
A prediction depends entirely on the data, rules and formulae the model was built from, so a factor left out (roadworks, a blocked drain, an out-of-date sensor reading) gives a confident but wrong result. Building an accurate model also needs skilled staff and time, and a complex model can need expensive hardware to run. One-off events nobody anticipated when the rules were written may not be predicted at all, so a human expert must still check and interpret the output.
Drawn from real examiner reports.
Computer model ≠ physical replica
Candidates picture a small card bridge, or a weather station full of instruments. A computer model is software: it represents the real bridge or weather system with data and mathematical rules, and predicts what a changed variable would do. Nothing physical is built or measured to produce that prediction — measuring equipment only supplies the data the model then uses.
s23 P12 Q13 · w23 P13 Q6 · w22/s22 model Qs
"It is safer" is a benefit, not an advantage
An advantage must compare with the real-world alternative; a bare benefit does not. "It is safer", "it is cheap", "it is quick" score nothing. Say what it is safer or cheaper THAN: safer than building and load-testing the real bridge; cheaper than waiting for a real flood to test a defence. The comparative word is what carries the mark.
s23 P12 Q13 · w23 P13 Q6 · w22/s22 model Qs
A comparison with no "because"
"Modelling a flood is cheaper than waiting for a real one" is a comparison but still not an explanation. Explain and describe questions want the second half: because no real property is damaged while different defence options are tried in the model. The comparative alone caps the mark — every explain point needs its reason attached.
s23 P12 Q13 · w23 P13 Q6 · w22/s22 model Qs
Generic computer benefit, not a modelling one
"Computers are fast" or "computers store lots of data" could be written for any ICT topic, so they do not answer a modelling question. Name what is being compared — the real bridge, the real flood, the real traffic jam, or a human working it out by hand — and tie the advantage to that: "unlike building the real junction, a model can be re-run with a new layout in minutes".
"Computers can go wrong" is not the reason
When a model's prediction fails to match reality, blaming the computer in general earns nothing. The fault is that the data and rules the model was built from did not fully represent the real situation — a missing factor, out-of-date readings, a faulty sensor. Name the specific input or rule that was wrong, not the machine.
Modelling ≠ computer-controlled systems
A computer model predicts an outcome; it does not operate anything. Robots, autonomous vehicles and 3D printers are computer-controlled systems — a different sub-topic — and offering one as a modelling application scores nothing. Stick to the five named contexts: personal finance, bridge and building design, flood-water management, traffic management, weather forecasting.
Name the application and the what-if
Read the scenario, state which of the five named contexts it is, then say which variable is being changed and what outcome is predicted — the interest rate, the wind speed, the rainfall total, the traffic-light timing, the temperature reading.
Use the sentence template
Write every advantage as: modelling is [safer/cheaper/faster] THAN [the real alternative] BECAUSE [reason]. No comparative means you wrote a benefit; no "because" means you did not explain. Check both words are present before moving on.
Discuss means both sides, in prose
Give at least one advantage AND one disadvantage, each a full comparison sentence. Do not split it into two columns with a vertical line — it prevents a true comparison and caps the marks. Answer every part of the scenario, and justify any evaluation, never just a preference.
Computer model -- software that represents a real-life situation, object or system using data, rules and formulae, allowing a user to answer "what-if" questions by changing a variable and seeing the model's predicted effect, without doing anything to the real thing.
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