<![CDATA[Background: This study aims to develop and produce a diagnostic tool capable of detecting student misconceptions on the concept of ecosystems. Methods: This study used a research and development method with a modified 4D design (Define, Design, Develop and Disseminate) without disseminating or spreading. Data collection methods used in this research and development are observation, literature review, documentation, questionnaires, interviews and tests. Results: The results showed that the instruments developed were valid by validating 3 experts, namely material experts, evaluation and assessment experts, and linguists with an average percentage of each feasibility of 90% material expert judgment, 82% assessment expert assessment and evaluation. and 80% linguist assessment. Meanwhile, the instrument readability test showed a percentage of 63% in good category. The validity value of the instrument in general was 0.70 with the valid or high validity category, while the instrument reliability value was 0.82 with the very high category of reliability. The overall results of students' misconceptions on ecosystem material showed 23% of students experienced low-category miconceptions, 8% of students experienced no conceptual understanding, 17% of students experienced conceptual understanding, and 52% of students experienced partial understanding. Conclusion: Based on these results it can be said that the four-tier test instrument developed is feasible and can diagnose misconceptions in students]]>
