Lesson 9: Evaluating the Investigation: Validity & Reliability (Excellence)
Carrying out a practical biological investigation with direction into a biological context.
🎯 Ngā Whāinga Akoranga | Learning Intentions
Excellence evaluation criteria for NCEA Level 1 Biology (Internal): evaluating how controlled variables were maintained, identifying sources of error/limitations, justifying equipment choice, and comparing findings to published scientific literature.
Write an Excellence-level evaluation detailing how key variables were controlled, discussing limitations, and validating findings against scientific sources.
🎥 Media Anchor & Pedagogical Scaffold
Evaluating Scientific Validity & Limitations for Excellence
Video Clip: Working Scientifically — Evaluating the Investigation: validity, reliability, and sources of error (Alex Lee) (Runtime: 10m 12s).
🧠 1. Before Viewing (Activate & Predict)
What separates an Achieved/Merit report from an Excellence evaluation that critically audits experimental validity?
👁️ 2. During Viewing (Watch With a Job)
- Validity vs reliability: define each term using the video's explanation. A result can be reliable without being valid — explain how.
- Sources of error: the video lists types of errors. Identify ONE random error and ONE systematic error that could affect your biology investigation. Describe the effect of each on your results.
- Improvements: for each source of error you identified, suggest a specific improvement to your method that would reduce it.
🗣️ 3. After Viewing & Kaiako Move (Process & Apply)
Kaiako Move: Model Excellence evaluation paragraphs analysing why specific variable control measures were successful or flawed.
Immediate Task: Complete Section 9 of your Investigation Log: Excellence Evaluation & Literature Comparison Report.
⚡ Whakaoho | Do Now: Investigation Recall (10 mins)
'I would be more careful next time' earns nothing. Neither does 'we could use better equipment'.
Two minutes: think of one thing that genuinely could have shifted your results, and write it with three parts — what it was, which direction it pushed your data, and what specifically you would change. That three-part shape is what an Excellence evaluation looks like.
📖 Activity 1: Investigation Planning & Practical Execution (25 mins)
Separate the two (12 min). Sort your investigation's weaknesses into validity problems (you measured the wrong thing, or something else caused the change) and reliability problems (your measurements scatter). They need different fixes, and mixing them up costs marks.
Compare to published work (13 min). Find a published value or trend for your reaction. Compare it to yours. If they disagree, propose which of your limitations best accounts for the gap — a specific one, with a direction.
📝 Activity 2: Level 1 Biology Investigation Log & Merit/Excellence Scaffolding (20 mins)
Report — Section 9. Submit: (1) your weaknesses sorted into validity and reliability with a fix for each; (2) your three-part statement for the most significant limitation; (3) your comparison with published data and a reasoned account of any difference.
🏫 Kaiako Planning & Pedagogy Notes
NCEA Level 1 Alignment: Direct preparation for NCEA Level 1 Biology — Internal (Carry out a biological investigation with direction). Emphasise complete variable control, accurate data processing, and clear biological explanations for Merit/Excellence grades.