Findings from the TIMSS 2019 Problem Solving and Inquiry Tasks

Ina V.S. Mullis, Michael O. Martin, Bethany Fishbein, Pierre Foy, and Sebastian Moncaleano

Chapter 4: Science Grade 8

Pepper Plants

Screen 5 – Experimental Setup: Other Variables

Following Screen 4 which dealt with the central experimental design (assigning amounts of the two fertilizers to experimental and control tanks), Screen 5 asked students to consider other factors that could affect the growth of their seedlings. Students were awarded full credit (2 points) for providing two correct responses (e.g., amount of light, enough water, temperature) and partial credit (1 point) if only one correct response was given.

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Maximum Score Points: 2
Content Domain: Biology
Topic Area: Ecosystems
Cognitive Domain: Knowing


Exhibit 47 shows that across countries on average, 54 percent of students correctly provided two things other than fertilizer that could affect the growth of their pepper plants, and a further 21 percent provided one thing. In Finland, the United States, and Singapore, 70 percent of students or more obtained full credit in this item. Girls performed better than boys, on average across countries (58% vs. 51%).