An apparatus to reduce iterative computation efforts for an advertisement campaign, the apparatus comprising: a publisher data retriever to retrieve, from a publisher, user identifiers associated with purchase instances; a household determiner to determine households that correspond to respective ones of the user identifiers; a buyer type determiner to determine a first group type and a second group type, the first group type associated with respective user identifiers exhibiting a first threshold of purchase behaviors, and the second group type associated with respective user identifiers exhibiting a second threshold of purchase behaviors; a holdout group identifier to identify (a) a first holdout group of the user identifiers of the first group type and (b) a second holdout group of the user identifiers of the second group type, the first and second holdout groups indicative of candidate user identifiers to be prevented from exposure to the advertisement campaign; a ratio constrainer to: reduce computational lift calculation resource consumption by constraining the first holdout group and the second holdout group to a same holdout ratio of households to generate a first constrained holdout group and a second constrained holdout group, respectively; and constrain the second holdout group to a second percentage of the second group type, the first percentage equal to the second percentage; and a lift calculator to calculate a lift value for each of the first group type and the second group type based on the first constrained holdout group and the second constrained holdout group a publisher data retriever to retrieve, from a publisher, user identifiers associated with purchase instances; a household determiner to determine households that correspond to respective ones of the user identifiers; a buyer type determiner to determine a first group type and a second group type, the first group type associated with respective user identifiers exhibiting a first threshold of purchase behaviors, and the second group type associated with respective user identifiers exhibiting a second threshold of purchase behaviors; a holdout group identifier to identify (a) a first holdout group of the user identifiers of the first group type and (b) a second holdout group of the user identifiers of the second group type, the first and second holdout groups indicative of candidate user identifiers to be prevented from exposure to the advertisement campaign; a ratio constrainer to: reduce computational lift calculation resource consumption by constraining the first holdout group and the second holdout group to a same holdout ratio of households to generate a first constrained holdout group and a second constrained holdout group, respectively; and constrain the second holdout group to a second percentage of the second group type, the first percentage equal to the second percentage; and reduce computational lift calculation resource consumption by constraining the first holdout group and the second holdout group to a same holdout ratio of households to generate a first constrained holdout group and a second constrained holdout group, respectively; and constrain the second holdout group to a second percentage of the second group type, the first percentage equal to the second percentage; and