Hi Seul, In your sentence, your main idea is that pre-market data is essential for making a decision to approve the device. To describe the purpose of something, you can use the preposition "for": "Post-market clinical studies are not intended to replace the pre-market data necessary for making the decision to approve the device." We use "so as to" to express a condition that is satisfied so that something else can happen. Example: They collected enough data so as to support their hypothesis. In this example, they had to collect sufficient data BEFORE they could support their hypothesis. Even if you were to use "so as to" in your sentence: "Post-market clinical studies are not intended to replace the pre-market data necessary to make the decision [so] as to approve the device", it sounds odd because we are not making a decision as a pre-requisite for approving a device. The decision itself is made to either approve or disallow the use of a device. Instead, the pre-market data must be collected as a pre-requisite before a decision can be made on the approval. Therefore, it would be better to modify the sentence like this: "Post-market clinical studies are not intended to replace the pre-market data which must be collected so as to facilitate the decision to approve the device." * There may be other better ways of expressing the intended meaning. Mine is just one of them. I hope this helps.

No. In this situation, "so as to", the "so" means "and for this reason". However, in this kind of non-creative writing, it is better to remove all such superfluous terms and words and be more concise and brief. I would rewrite the sentence as "Post-market clinical studies are not intended to replace pre-market data IN makING the decision to approve the device"

I dare to believe that there will be some comments upon my explanation very soon! So, before I am judged by the answer I have just provided, I will leave here a link to the source of my explanation: https://www.thefreedictionary.com/as Hope this helps - Feel free to contact me whenever you please!

Hey Seul, how are you? As opposed to Jeff and Mr. Lance, whose answers were rather interesting, I should think otherwise and provide you with a different explanation. Firstly, you should know that the idiom ''so as to'' means ''in order to; with the intention of''. If you were to omit the word ''so'' from the expression, it would then be reduced to ''as to'' and many people would say that it would be wrong to use it in such a context, since ''as to'' means ''with respect to; regarding (something)''. As a matter of fact, the expression ''as to'' is used to convey the aforesaid meaning, but it can also be used to mean ''with the result that''; ''that the result is/was'' or simply ''to'' (rarely used as a shortened form of ''so as to''). For this reason, as regards the context you provided ''Post-market clinical studies are not intended to replace the pre-market data necessary to make the decision as to approve the device'', you might get the idea that ''...as to approve...'' is being used in the sense of ''...(in order) to approve'' or ''...with the result/intention to approve...'' *NOTICE: The idiom ''as to'' is usually used to mean ''with reference to (in/with regard to)'', but seldomly is it used in the sense of ''with the result/intention that'' - it might be used, however. May I provide you with a set of examples, for a better understanding: 1) ''So as to'' = in order to; with the intention of. E.g.: ''I studied hard so as to pass the exam.'' E.g.: ''She ran away so as not to get caught.'' 2) ''As to'' = when used in the sense of ''with respect to (regarding...)''. E.g.: ''As to him, I am not worried.'' E.g.: ''I'm willing to read his book, but as to publishing it, that's a different matter.'' 2.1) ''As to'' = when used in the sense of ''that the result/effect is/was'' (rare usage). E.g.: ''His voice was so loud as to make everyone stare.'' E.g.: ''He was so foolish as to lie.'' E.g.: ''He's not so silly as to do that.'' Hope that helps!!!