Quality Assured: Rethinking Annotation Strategies in Imaging AI
This work addresses the problem of generating high-quality annotations for imaging AI, which is crucial for reliable benchmarking and real-world applications, but it is incremental as it focuses on evaluating existing practices rather than introducing new methods.
The paper studied the impact of quality assurance processes in annotation companies on annotation quality, finding that annotation companies outperform Amazon Mechanical Turk in quantity and quality, but internal QA provides only marginal improvements, while better labeling instructions can substantially boost performance.
This paper does not describe a novel method. Instead, it studies an essential foundation for reliable benchmarking and ultimately real-world application of AI-based image analysis: generating high-quality reference annotations. Previous research has focused on crowdsourcing as a means of outsourcing annotations. However, little attention has so far been given to annotation companies, specifically regarding their internal quality assurance (QA) processes. Therefore, our aim is to evaluate the influence of QA employed by annotation companies on annotation quality and devise methodologies for maximizing data annotation efficacy. Based on a total of 57,648 instance segmented images obtained from a total of 924 annotators and 34 QA workers from four annotation companies and Amazon Mechanical Turk (MTurk), we derived the following insights: (1) Annotation companies perform better both in terms of quantity and quality compared to the widely used platform MTurk. (2) Annotation companies' internal QA only provides marginal improvements, if any. However, improving labeling instructions instead of investing in QA can substantially boost annotation performance. (3) The benefit of internal QA depends on specific image characteristics. Our work could enable researchers to derive substantially more value from a fixed annotation budget and change the way annotation companies conduct internal QA.