If the ethical approval of the the first study involved considerations about the purposes for which the data was collected in and those purposes are different in the second study, then a new approval is needed even if the data is unchanged. But generally in the interest of streamlining, bureaucratic procedures require separate approvals for separate studies; cross-indexing separate studies could lead to inefficiencies in the process.

If the ethical approval of the the first study involved considerations about the purposes for which the data was collected in and those purposes are different in the second study, then a new approval is needed even if the data is unchanged. But generally in the interest of streamlining, bureaucratic procedures require separate approvals for separate studies; cross-indexing separate studies could lead to inefficiencies in the process.

Would depend, I suspect, in part on the nature of the data. If it is highly specific, detailed clinical data or is it more general, anonymize data? Either way, the appropriate course is to ask the original collector/author for permission to use data. He or she will be in the best position to give or withhold approval. And, of course, if you do use it be sure to credit the original researcher and the reasons for your approved use.

Ah, an ambiguity in the question. I assumed the 2nd study was to be undertaken by the same person as the first whereas Tom Koch assumes the 2nd study reuses data previously collected by a different person for their study. Which situation does your question pertain to, Alain Mwamba Mukendi ?

@karl Pfeifer

DATA were collected by me and I used them for one study.

So, if it is data you collected for the first study and that you wish to use in a second report there should be no problem. My assumption is that in the second paper the discussion and focus is related, but distinct. Thus you will need to repeat data on the ethical standards of the study, means of collection, etc. And reference its earlier use.