Analysis of Sales Promotion Effects on Household Purchase Behavior

promotional post-promotional purchased volume ( q + ). The four purchase quantity
measures are as follows (again using ratio measures for normalization purposes):
( 8)
Quantity Before effect:
QB =
q−
−
q
q
.
The quantity before effect is the relative change <strong>of</strong> the pre-promotional purchase quantity
(expected to be ≤ 0).
q0
− q
( 9)
Quantity <strong>Promotion</strong>al
effect : QP = .
q
The quantity promotional effect is the relative change <strong>of</strong> the promotional purchase quantity
(expected to be ≥ 0).
( 10)
Quantity After effect : QA =
q+
−
q
q
.
The quantity after effect is the relative change <strong>of</strong> the post-promotional purchase quantity
(expected to be ≤ 0).
( 11)
Quantity Net effect : QN = ( QB + QP + QA)
/ 3 =
(( q−
+ q0
+ q+
) / 3)
− q
.
q
The quantity net effect is the intertemporal net relative change in purchase quantity.
We doubt whether the quantity before effect (QB) is significant. If so, it is expected to be
negative (anticipation effects). We do expect the two other effects to be present. The
quantity promotional effect (QP) is expected to be positive, households buying more <strong>of</strong> a
product when it is on promotion. However, there are also counter-arguments. The quantity
promotion effect could be negative if households are less willing to take risks for a nonfavorite
brand. A large positive time acceleration effect could also go hand in hand with a
negative quantity effect, as a result <strong>of</strong> the higher average remaining stock at the purchase
time. The quantity after effect (QA) is expected to be negative, due to possible
promotional stockpiling effects. The sign <strong>of</strong> the quantity net effect (QN) depends on
whether or nor changes in purchase time take place. Extra promotional purchases can lead
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