If a company announces that it plans to host a conference call after the quarterly fiscal report is released, is that predictive of the relative success of that quarter? Is it more likely to be celebratory or could it be preparing to soften the blow? Or are conference calls so commonplace that it is not necessarily an indicator either way?
It's very common and I doubt it holds any predictive power:
Results from the 2014 Earnings Call Practices Survey conducted by the National Investor Relations Institute (NIRI), a professional association of corporate officers and investor relations consultants, confirm that an overwhelming majority of public companies hold quarterly earnings calls—97 percent of the companies that responded to the survey report holding such calls.
Applicable rules, including Regulation FD and the safe harbor in Item 2.02(b) of Form 8-K for oral disclosures made during an earnings call, require companies to provide advance notice of earnings calls. Companies share approaches when it comes to making these earnings call announcements: press releases and posts on company websites are the most common methods (93 percent and 83 percent, respectively).
Most established companies hold a conference call and the existence of such has no predictive value whatsoever. For a list of upcoming conference calls, Google: "earnings conference call calendar". You'll find lots of web sites listing them.