Development of a Lac Operon Concept Inventory (LOCI)

Area of Science:

• Genetics Education
• Molecular Biology

Background:

• Concept inventories (CIs) are crucial for evaluating student learning and identifying misconceptions.
• Gene regulation, particularly the lac operon, presents significant challenges for undergraduate students.

Purpose of the Study:

• To develop and validate a multiple-choice concept inventory to assess undergraduate student understanding of the lac operon.
• To identify common student errors and misconceptions regarding gene regulation.

Main Methods:

• Development of open-ended questions followed by in-class testing with undergraduate students.
• Construction of a 12-item multiple-choice inventory (LOCI) based on initial findings.
• Content validation by experts, followed by item analysis and reliability testing (coefficient alpha = 0.994) with 115 genetics students.

Main Results:

• The Lac Operon Concept Inventory (LOCI) demonstrated high reliability and validity.
• Item analysis indicated adequate discriminatory power and item difficulty.
• The LOCI effectively assesses student knowledge of the lac operon.

Conclusions:

• The LOCI is a valuable and psychometrically sound tool for educators to assess student understanding of the lac operon.
• The inventory can inform instructional strategies to address common misconceptions in gene regulation.
• This CI contributes to improving the teaching and learning of fundamental genetics concepts.