Most certiorari petitions die before any full-Court conference vote occurs.

Evidence

The chief justice prepares and circulates a “discuss list,” which includes the cases he believes warrant collective consideration, and other justices may add cases to the list. Unless a justice requests that a petition be discussed at conference, the petition is denied. More than 70 percent of all petitions for certiorari are thus disposed of before conference. … If four justices vote to hear a case, the so-called Rule of Four, it is accepted for review and scheduled for oral argument. If fewer than four justices favor review, the petition for certiorari is denied, and the decision of the lower court stands. — G. Alan Tarr, Judicial Process and Judicial…, 1508