[![OPAQ][1]][2] **What is [OpAQ][3]?** Research on anchoring effects is currently challenged by the lack of reliability of anchoring scores, a large amount of heterogeneity between anchoring effect sizes, and by numerous contradictory findings. With OpAQ, we try to solve these problems by providing an open, free, and ever-growing dataset already containing thousands of trials from several studies on anchoring effects. **What are your benefits of joining us?** You are very welcome to contribute data from your anchoring experiment(s)! In return, (apart from being rewarded by the good feeling of helping research on anchoring effects to improve) we will list you as a contributor on the OpAQ website. If you send us your data, we can convert it and add it to the OpAQ dataset. You can also use our data curation template and convert your data yourself. Accordingly, we will mention your contribution either as “Resources” or additionally as “Data curation”. Unpublished datasets as well as data from classroom experiments are also highly appreciated. **What can you do with the OpAQ dataset?** The OpAQ dataset can be accessed and downloaded via our ShinyApp (https://metaanalyses.shinyapps.io/OpAQ/) or our OSF project (https://osf.io/ygnvb/). In our [ShinyApp][4], you can explore the dataset and the dynamic meta-analysis on anchoring effect sizes and the reliabilities of anchoring susceptibility scores. The dataset also provides the opportunity to test additional hypotheses, such as file-drawer-effects, effects of anchor extremeness, or age effects. In the [OSF project][5], you can find further information and files on our project. There, you also can send us a contribution request to the project (make sure to also send us an e-mail after you requested access). **What does the OpAQ dataset look like?** The OpAQ dataset is an item-based dataset with a row for every single estimation of all the anchoring items it contains. For every estimate, different variables and anchoring scores are specified. We also provide a [text file][6] with descriptions of all variables that are included in the dataset. For questions, please send an e-mail to lukas.roeseler(at)uni-bamberg.de **I noticed an error in the dataset, what should I do?** Please notify us about the error using the [error notification form][7], [1]: https://metaanalyses.shinyapps.io/OpAQ/_w_bd27f6a8/opaq.png [2]: https://metaanalyses.shinyapps.io/OpAQ/ [3]: https://metaanalyses.shinyapps.io/OpAQ/ [4]: https://metaanalyses.shinyapps.io/OpAQ/ [5]: http://OSF%20project [6]: https://osf.io/j2xmt/ [7]: https://osf.io/htb2q/