Effects of a science center outreach lab on school students' achievement – Are student lab visits needed when they teach what students can learn at school?

68 ninth-grade classes, N = 1,773 students

German ninth-grade students (age ~15), secondary schools in Baden-Württemberg; chemistry of starch.

Cluster-randomised at class level (68 classes) to four arms: (1) School only — lab work delivered in the ordinary classroom; (2) SCOL only — the same unit delivered at a science-centre outreach lab; (3) SCOL & school — combined; (4) control. Pretest-posttest achievement. THE LIMITATION THAT MATTERS: all three treatment arms are lab-work arms. There is no arm that teaches the same starch chemistry content WITHOUT practical work. So the trial cleanly identifies WHERE lab work should happen (in school vs at a science centre), and cleanly identifies taught-vs-untaught, but it does NOT isolate the causal contribution of the hands-on component itself — the treatment-vs-control contrast is confounded with simply receiving a taught unit on the topic. The research group also ran the outreach-lab programme being evaluated, hence developer-involved. Outcome is a researcher-built starch-chemistry achievement test aligned to the unit.

One of very few genuinely cluster-randomised trials of school lab work anywhere in the K-12 literature — and the single best-identified one in this file. 68 ninth-grade classes (1,773 students) were randomised to receive a starch-chemistry lab unit at school, at a science-centre outreach lab, in both, or not at all. All three lab arms outperformed the untaught control on the achievement posttest, which is the unsurprising 'teaching beats not teaching' result. The informative contrast is within the lab arms: the ordinary classroom arm and the combined arm BOTH beat the glamorous science-centre-only arm on achievement. The expensive, specialised, out-of-school lab setting bought motivation, not learning. What the trial cannot tell you — because no arm was taught the same content without practical work — is whether the hands-on component contributed anything over an equally long non-practical lesson on starch chemistry.

Low. Randomisation is at class level, so genetic differences cannot differ systematically between arms.

The same trial is reported with different outcomes in Itzek-Greulich et al. 2017 (Contemporary Educational Psychology, motivation and achievement) and Itzek-Greulich & Vollmer 2017 (JRST, emotional/motivational outcomes in the intermediate track). These are companion papers from ONE trial, not independent replications. No independent replication of the design is known.