How to Score Higher in SQA Higher Computing Science ()

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'Describe' means state what a piece of code or system does, step by step, in plain terms — quote variable names, values, and conditions from the code. 'Explain' means state what happens and why it happens in that context. Before answering, identify the command word and commit to it: a 'describe' answer needs no 'because'; an 'explain' answer always needs 'because' or 'so that'. Use the specific scenario or code provided — generic descriptions of how a loop works in theory do not earn marks.

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A boundary is the specific value at which the program must behave differently — it must be derived from the scenario, not copied from it. For example, if the stem says a discount applies to orders over £100, the boundary is £100 (and £101, the first value that qualifies). Identify what changes at that point. For functional requirements, always name the underlying code construct: 'a query to search for…', 'a form element to…', or 'a JavaScript function to…' — never just reword the user requirement.

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For each sub-program, ask: what data does it need that it does not already have? That is the IN parameter. What data does it produce that the calling program needs? That is the OUT parameter or return value. Do not pass variables the sub-program does not use — unnecessary parameters lose marks. Distinguish arrays from non-array variables in data flow diagrams: arrays use brackets (e.g. scores[]) while single variables do not.

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Evaluation at Higher must reference the specific sub-program, variable, loop, or data structure named in the question. Phrases such as 'the code is efficient because it uses meaningful variable names' are National 5 standard and earn no marks. Instead write: 'the search sub-program is efficient because it uses a linear search that exits as soon as the target is found, reducing the number of iterations on average.' Always re-read the question and confirm your answer references the exact aspect it asks about.

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A local variable is declared inside a sub-program and cannot be accessed outside it. The maintainability benefit is that changing a local variable inside one sub-program cannot accidentally affect other sub-programs — making it easier to debug and modify individual modules without unintended side-effects. Always frame your answer around the context of the code given, naming the variable and sub-program shown in the question.

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GROUP BY is required whenever you use an aggregate function (COUNT, SUM, AVG, MAX, MIN) and also want to display a non-aggregate field. Without GROUP BY, the database cannot determine how to group rows for the aggregate. To explain it: 'GROUP BY fieldName is required so that the COUNT is calculated separately for each unique value of fieldName, not across the whole table.' Also name the specific field in the question — 'missing GROUP BY' alone is not specific enough.

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A functional requirement for a web page must identify what the code will do, not what the user sees. Instead of 'the user can submit their details', write 'a form with text input elements and a submit button to collect and validate user details using JavaScript'. Always name the HTML element type (form, input, select, button) or the JavaScript mechanism (event handler, validation function). Database functional requirements should reference query types: 'a query to search the Orders table using a WHERE clause'.

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Standard algorithms (linear search, find minimum/maximum, count occurrences) must be written as explicit refined pseudocode steps — not as a single call to a built-in sort or max function. For each algorithm, write the initialisation step, the loop condition, the comparison inside the loop, and the update step. The marking instructions assess the constructs used, not just whether the output matches. A language's built-in max() function earns no marks if the question asks you to design the algorithm.