More research is not needed

Try typing the search term "more research is needed" (with the quote marks) into PubMed:  

http://www.ncbi.nlm.nih.gov/pubmed?db=pubmed. You should get over 62,000 hits, and that's only for papers which have the phrase in their abstract. Countless more will have it buried in the discussion section of the full text. In fact, it would be interesting to know which papers don't advocate carrying out further research. 

To be fair, sometimes this conclusion may be appropriate. More research is needed if one reports an equivocal result or a finding which is unexpectedly negative or unexpectedly positive. More research is needed if insufficient information has been obtained in order to come to a reasonable conclusion as to what clinical interventions may be appropriate or what theoretical insights have been gained. More research is needed if one has obtained a positive result but its exact implications require further clarification. 

However more research is not needed if a hypothesis has been tested using a reasonable methodology and an adequate sample size and the conclusion is pretty much in line with what a prior understanding of the field might have predicted.  

Typically, if one group has reported a weakly significant finding from a genetic association study and a follow-up study in a large sample is negative then the people reporting the negative study do not have to say that "more research is needed". They can just say they failed to replicate the result and everybody can move on.  

If trials of complementary therapy are negative then it does not mean that "more research Is needed". It means that the complementary therapy probably doesn't do any good. 

Take a look at this site discussing complementary therapies for asthma: http://www.asthma.org.uk/about-asthma/medicines-treatments/complementary-therapies/ 

Note this phrase in the introduction (my italics): "Because they have not been studied as extensively as conventional medicines, there is little scientific evidence to show that complementary therapies are effective..." The "Because" there seems to imply that if only they were studied more extensively then the evidence that they were effective would appear. Erm, maybe not. 

And then we have this: "Although some research has shown homeopathy to be helpful in asthma, more research is needed to study larger groups of people." There's no citation for the "research" so it's hard to know what this claim is based on. Actually, the available research seems to show that homeopathy has no effect at all, which is exactly what one would expect. So, no, more research is not needed. But saying that it is needed implies that there might be something there to discover, else why bother doing it? 

Come on people, we're well into the 21st century. More research is not needed into whether witches can cast spells or whether melancholia is caused by an excess of black bile. More research is not needed into homeopathy, iridology,  naturopathy or a whole bunch of other nonsense. 

And if you're doing proper research and you get a negative result, you don't have to say that more research is needed just to be polite.