If your registered trademark or trademark application ends up going in to litigation against another trademark, then a major issue is usually whether or not there is actual confusion with the other trademark. If this is the case, then here are a few things which could be considered evidence of actual confusion: testimony from consumers that experienced confusion and testimony or documents demonstrating mistaken or misdirected mail, orders, or phone calls. Other things may also be evidence such as a boon in sales after infringement or even investigations by secret shoppers. There are also many things that will likely not be considered evidence and may be considered inadmissible hearsay. Statements repeating statements by others, employee conversations which cannot be verified, documents unavailable for cross-examination, infrequent examples of confusion, and evidence with lacks a guarantee of trustworthiness. Survey evidence may be admissible if it meets certain high standards. Such surveys must be created by an independent expert, the survey must be given to relevant consumers, such consumers must be chosen in an unbiased manner, and be given by trained and independent interviewers. The questions must be clear, precise, and not lead the consumer. All data has to be reported and analyzed accurately and by accepted standard. The right evidence can help bolster your case.
This blog is not legal advice and is not specific to your application. You should always consult an attorney.