From Goldberg v. UBS AG, 2010 U.S. Dist. LEXIS 19754 (E.D.N.Y. Mar. 5, 2010):

A district court has the discretion to certify an order for interlocutory appeal pursuant to 28 U.S.C. § 1292(b) if the court "is of the opinion that: (1) the order 'involves a controlling question of law'; (2) 'as to which there is substantial ground for difference of opinion'; and (3) 'an immediate appeal of the order may materially advance the ultimate termination of the litigation.'" *** Because an interlocutory appeal may "prolong judicial proceedings, add delay and expense to litigants, burden appellate courts, and present issues for decisions on uncertain and incomplete records, tending to weaken the precedential value of judicial opinions," *** "only 'exceptional circumstances [will] justify a departure from the basic policy of postponing appellate review until after the entry of a final judgment.'" *** "Appeal is limited to those instances where the movant demonstrates the existence of exceptional circumstances sufficient to overcome the general aversion to piecemeal litigation." *** "[D]istrict court judges have broad discretion to deny certification even where the statutory criteria are met." ***

Section 1292(b)'s requirement that there be a "substantial ground for difference of opinion" may be met where there is "substantial doubt that the district court's order was correct;" *** where "there is conflicting authority on the issue;" or where the issue "is particularly difficult and of first impression for the Second Circuit." *** However, the Second Circuit has held that the "mere presence of a disputed issue that is a question of first impression, standing alone, is insufficient to demonstrate a substantial ground for difference of opinion." In re Flor, 79 F.3d 281, 284 (2d Cir. 1996); see also Carbotrade SPA v. Bureau Veritas, \No. 92-CIV-1459 (RPP), 1993 WL 60567, * 1 (S.D.N.Y. March 2, 1993) ("[Defendant has] failed to present a single case or other legal authority showing that there is 'substantial doubt' that this Court was correct. . . . The defendant correctly asserts that this issue is one of first impression. Though relevant, this fact does not, without more, suffice to present a 'substantial ground for difference of opinion' under 28 U.S.C. § 1292(b).")***

[Footnote 18] The novelty of an issue may counsel against certification because interlocutory appeal would require the Second Circuit to decide an issue without the benefits afforded by a full record. ***