Q: Can I submit a full paper based on a short paper that is not yet published?

First of all, are you sure that you need to write two papers on the same topic? If you have already done with the empirical study, is there any need to publish the short paper? I hope you are aware that this might be regarded as salami slicing, that is, the practice of using the same data to publish multiple papers when it could have been published as a single study. If you are doing this just to increase your publication count, it is highly unethical. According to the Office of Research Integrity (ORI), it is unethical to partition a study into multiple papers if the results are best presented as a ‘cohesive’ single whole.

However, having said that, not all related studies are unethical. If you have strong reasons for publishing a short paper first and then developing it into an empirical study, you can go ahead. However, you should cite the short paper in the second article and mention that you had communicated this finding earlier. However, to do that, you must wait for the short paper to be published or at least accepted by the journal. Once it is accepted, you can cite it with the words "accepted for publication" in brackets after the journal name.