One challenge that can discredit the evidence is that many types of analysis rely on standard operating procedures meaning that lab reports would be repetitive and unduly consumptive of time (Houck, 2015). Also scientists are called to testify in many situations about methods, procedures, results and conclusions concerning a particular case. If a trial occurs shortly after after the evidence was analyzed, then the scientist should be able to testify directly from memory. There are times that the trial does not occur months or years later and the lab report has to used to memorialize the evidence. The scientist needs to stay within their areas of expertise and not be tempted to answer questions or speculate an answer.