TY  - JOUR
AB  - Purpose Ensuring quality is one of the most significant challenges in microtask crowdsourcing tasks. Aggregation of the collected data from the crowd is one of the important steps to infer the correct answer, but the existing study seems to be limited to the single-step task. This study aims to look at multiple-step classification tasks and understand aggregation in such cases; hence, it is useful for assessing the classification quality.Design/methodology/approach The authors present a model to capture the information of the workflow, questions and answers for both single- and multiple-question classification tasks. They propose an adapted approach on top of the classic approach so that the model can handle tasks with several multiple-choice questions in general instead of a specific domain or any specific hierarchical classifications. They evaluate their approach with three representative tasks from existing citizen science projects in which they have the gold standard created by experts.Findings The results show that the approach can provide significant improvements to the overall classification accuracy. The authors’ analysis also demonstrates that all algorithms can achieve higher accuracy for the volunteer- versus paid-generated data sets for the same task. Furthermore, the authors observed interesting patterns in the relationship between the performance of different algorithms and workflow-specific factors including the number of steps and the number of available options in each step.Originality/value Due to the nature of crowdsourcing, aggregating the collected data is an important process to understand the quality of crowdsourcing results. Different inference algorithms have been studied for simple microtasks consisting of single questions with two or more answers. However, as classification tasks typically contain many questions, the proposed method can be applied to a wide range of tasks including both single- and multiple-question classification tasks.
VL  - 3
IS  - 3
SN  - 2398-7294
DO  - 10.1108/IJCS-06-2019-0017
UR  - https://doi.org/10.1108/IJCS-06-2019-0017
AU  - Bu Qiong
AU  - Simperl Elena
AU  - Chapman Adriane
AU  - Maddalena Eddy
PY  - 2019
Y1  - 2019/01/01
TI  - Quality assessment in crowdsourced classification tasks
T2  - International Journal of Crowd Science
PB  - Emerald Publishing Limited
SP  - 222
EP  - 248
Y2  - 2024/04/18
ER  -