With the increasing prosperity of online marketplaces, millions of items are available on a single plat-form. Due to the limited cognitive capacity of human beings, consumers make purchase decisions in a way that balances both effort and accuracy, as contended by the effort-accuracy trade-off (EATO) framework. However, we propose that the rich functionality of online decision support aids (DSAs), namely image-based searching, cross-platform comparison and collocation recommendation, can first simplify consumers’ information processing in terms of problem identification, alternative generation and product evaluation. DSAs can then help consumers achieve a high level of accuracy in the deci-sion elicitation and making process with minimal effort. We refer to this as effort-accuracy co-existence (EACE) that highlights the non-inversed relationship between effort and accuracy as well as the extended cognitive boundary in consumers’ purchase decision making. We plan to validate the conceptual model using experiments with online buyers. The proposed methodology and implications are discussed in this research-in-progress paper.