Can I say “lossy compression damages the file” in IB Computer Science?

You can, but it’s usually too vague for top marks in IB Computer Science. “Damages” sounds emotional, not technical. Examiners reward precision: say lossy compression removes information permanently to reduce file size. Then explain the impact: reduced quality or detail compared with the original. Finally, justify why it’s still used: faster transmission and lower storage costs. That chain of reasoning shows you understand the trade-off.

Why does lossless compression not always shrink files much?

In IB Computer Science, this comes down to redundancy. Lossless compression relies on patterns and repeated structures it can encode more efficiently. If a file is already compressed or has little repetition, there may be limited redundancy to remove. That’s why compressing a JPEG again with ZIP often barely helps. This is also why different data types behave differently under compression. Mentioning “file type” and “redundancy” is a strong signal to the examiner.

How should I revise lossy vs lossless compression quickly before an exam?

Start by mastering a two-sentence comparison you can write under pressure in IB Computer Science. Then use active recall: test definitions and examples with the Compression flashcards or browse IB Flashcards with spaced repetition. Next, convert knowledge into marks using the Questionbank and review feedback. If you get stuck explaining trade-offs, use RevisionDojo’s AI Chat to refine wording into examiner-style phrasing. Finally, build confidence by mixing quick concept review with timed questions from the IB Computer Science resources hub.