# Instructor perspectives on iteration during upper-division optics lab activities

## TL;DR

This study explores instructor perspectives on iteration in upper-division optics lab activities, identifying four types of iteration crucial for modeling, which informs future assessment development.

## Contribution

It provides a detailed qualitative analysis of how instructors perceive and implement iteration in optics labs, highlighting four distinct types of iteration relevant for modeling assessments.

## Key findings

- Iteration is considered important for modeling by many instructors.
- Four types of iteration are identified: revising apparatus, models, data procedures, and repeating data collection.
- Examples of each iteration type are provided to inform assessment design.

## Abstract

Although developing proficiency with modeling is a nationally endorsed learning outcome for upper-division undergraduate physics lab courses, no corresponding research-based assessments exist. Our longterm goal is to develop assessments of students' modeling ability that are relevant across multiple upper-division lab contexts. To this end, we interviewed 19 instructors from 16 institutions about optics lab activities that incorporate photodiodes. Interviews focused on how those activities were designed to engage students in some aspects of modeling. We find that, according to many interviewees, iteration is an important aspect of modeling. In addition, interviewees described four distinct types of iteration: revising apparatuses, revising models, revising data-taking procedures, and repeating data collection using existing apparatuses and procedures. We provide examples of each type of iteration, and discuss implications for the development of future modeling assessments.