System Combination WER

There is one thing I usually wonder about while reading the next conference paper on speech recognition. The usual paper limit is 4 pages and the authors usually want to write exactly 4 pages. What should you do if you don't have enough information? Right, you can build exactly same systems with PLP features and MFCC features and probably with some other features and you can add one more table about system combination WER and probably add one graph too or you can mix two types of LM and report another nice graph.

This practice has been started long long time ago during NIST evaluations I think, when participants reported system combination WER. NIST even invented ROVER algorithm for better combination.

For me personally such content in a paper reduces quality of the paper significantly. The system combination WER was never meaningful addition. Yes, it's well known that if you combine MFCC with PLP you can reduce WER by 0.1% and probably you will be able to win the competition. From scientific point of view this result adds zero new information, it just a filler for the rest of your paper. Also, to get a combination result of 5 systems you usually spend 5 times more computing individual results. Not worth for 0.1% improvement, you can usually get the same with slightly wider beams.

So instead consider doing something else, try to cover the algorithms you used and explain why do they work, try to describe the troubles you've solved, try to add new questions you consider interesting. At least try to collect more references and write a good overview on the previous research. That will save your time, reader's time and the computing power you used to build another model.


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