The first step in estimating Class-wide damages is to use standard regression
analysis to estimate any direct purchaser overcharge in the price of LIBs due
to the alleged conspiracy. Once estimated, any overcharge is then applied to
the value of LIBs purchased directly from defendants, to yield an estimate of
the value of world-wide aggregate damages.
 We conclude, therefore, that consistent with the approach
taken in the statement of claim, the methodology proposed by Dr.
Reutter addresses only the calculation of damages for direct and
indirect purchasers of LIBs manufactured by the defendants.
 In the absence of any explanation of how damages could be
quantified for the class as a whole, it is difficult therefore to say
that there is a “reasonable likelihood” that the conditions for s. 24
could be met. For this reason, the question of aggregate damages is
not certified as a common issue for the entire class. Dr. Reutter
has, however, provided a method offering a reasonable likelihood of
being able to determine the aggregate damages suffered by non-umbrella purchasers. This was accepted by the courts below as
they certified the calculation of aggregate damages for the class,
which then excluded the umbrella purchasers, as a common issue.
As a result, a subclass should be created for non-umbrella
purchasers with respect to the aggregate award of damages issue.
 The fact that damages cannot be assessed on an aggregate
basis for the class as a whole does not mean the action should not
proceed as a class proceeding. Furthermore, the question of
whether damages can be aggregated is ultimately a question for
the common issues trial judge. Failure to certify the question of
whether aggregate damages are available for umbrella purchasers
does not preclude a trial judge from invoking s. 24 if he or she
considers it appropriate once liability has been found: Pro-Sys, at
 Accordingly, the common issues certified are as follows:
(a) Did the defendants, or any of them, breach s. 45 the
Competition Act (which is contained in Part VI of the
Competition Act) giving rise to liability pursuant to s. 36 of
the Competition Act?
( i) Between January 1, 2000 and March 12, 2010, did the
defendants and/or any unnamed co-conspirators conspire,
agree or arrange with each other to
(A) prevent, limit or lessen, unduly, the manufacture
or production of lithium batteries; and/or
(B) enhance unreasonably the price of lithium