It is important to note distance does not appear as a separate
right-hand side variable in equation [6]. This exclusion comes from the
assumption that the distance to a lower-price jurisdiction impacts
smuggling but not quantity demanded, conditional on the decision to
smuggle. In other words, the model predicts distance does not belong in
X. In the regressions that follow, I include log distance in X as an
over-identification test of the exclusion restriction. (28)
RESULTS
Coefficient Estimates
Table 6 presents the results from the estimation of demand function
[6]. Panels A-C contain estimates for the intensive, extensive, and full
demand models, respectively. All three panels contain six columns of
results; I control for year trends in only even numbered columns.
Columns i and ii present estimates from the demand model ignoring all
smuggling incentives and geographic variability. Such a model is similar
to what other researchers have used when studying cigarette demand using
micro data and is useful in understanding the impact of accounting for
smuggling behavior. Columns iii-vi contain estimates from the demand
model outlined in the previous sections, with the final two columns
including Native American Reservations in the price difference and
distance variables.
In the specifications that account for smuggling, the coefficient
on log real home state price is negative and significant at either the
five or ten percent level. As this coefficient also represents the full
price elasticity, Table 6 illustrates, absent smuggling, that there is a
consistent negative relationship between price and consumption on the
intensive, extensive, and full margins.
The coefficient on the difference in log price, log distance
interaction variable is a central parameter in this study because it
describes how the responsiveness of demand to home state price changes
varies with distance to a lower-price border. In all relevant columns of
Table 6 (columns iii-vi), this coefficient is negative and is
significant at the five percent level in all but the final two columns
of Panel B. I estimate this coefficient to be around -0.2 in the
intensive and extensive demand models and between -0.58 and -0.42 for
the full model. Thus, the relationship between quantity demanded and the
home state price is quite sensitive to the distance to the closest
lower-price border. (29)
The coefficient on the difference in log price variable is positive
in all specifications, but is often not significant at either the five
or ten percent level. The estimates range from 0.69 to 1.06 on the
intensive and extensive margins and 2.17 to 2.55 on the full margin.
Finally, across all specifications in Table 6, the coefficient on the
difference In log price squared varies in sign but is not statistically
significant.
As discussed in the fifth section, the log distance variable does
not appear in equation [6] as a separate explanatory variable. The
inclusion of this coefficient provides an over-identification test that
excluding distance from the demand model is appropriate. In all three
panels, I find the coefficient on log distance to be small and not
statistically significant at the five or ten percent level. (30) This is
evidence that changes in distance do not affect consumption if the price
difference is zero; conditional on the decision to smuggle, distance has
no impact on quantity demanded.
Estimated Elasticities
The coefficient estimates shown in Table 6 yield insight into the
relationship between cigarette consumption, cigarette prices, and
distance. These effects can be summarized more simply by calculating the
home state and full price elasticities, which give the percent change in
cigarette consumption due to a one percent change in the home state
price and in all prices, respectively. Both elasticities can be
calculated from equation [6]:
[7] Home State Price Elasticity = [partial
derivative]ln(Q)/[partial derivative]ln([P.sub.h])
= [[PI].sub.1] + [[PI].sub.2] + 2[[PI].sub.3](ln([P.sub.h]) -
ln([P.sub.b])) + [[PI].sub.4]ln(D)
[8] [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]
Table 7 presents home state and full price elasticity estimates
calculated from the coefficients in Table 6. All panels and columns
correspond to the same specification from Table 6. In columns i and ii,
where geographic variability and smuggling incentives are ignored, the
home state and full price elasticities are identical by definition.
Thus, only the former statistic is shown. Robust standard errors are in
parentheses.
The home state price elasticities range from -0.03 to 0.08 on the
intensive margin, -0.06 to -0.02 on the extensive margin and -0.11 to
0.06 for the full margin. In no specification are these elasticities
differentiable from zero at the five or ten percent level. These numbers
imply, on average, in the presence of cross-locality price
differentials, home state price changes have a negligible effect on
cigarette demand.
The home state price elasticities contrast markedly and
statistically significantly with the full price elasticities, which
range from -0.18 to -0.10 on the intensive margin, -0.30 to -0.23 on the
extensive margin, and -0.53 to -0.44 on the full margin. These
elasticities are larger in absolute value than the home state price
elasticities, and the full margin elasticities are consistent with many
of the elasticity estimates from the taxable sales literature. (31) When
one adequately controls for cross-border purchases, it is possible for
the full price elasticities calculated using micro data to mirror the
estimates from the taxable sales literature.
A specific example is illustrative of the difference between the
home state and full price elasticities. In the last column of Panel C,
the home state price elasticity is 0.03 while the full price elasticity
is -0.53. This gap suggests while smoking is unresponsive to changes in
the home state price on average in the presence of casual smuggling, if
smuggling were eradicated, home state cigarette price elasticities could
reduce cigarette consumption. Due to the inelastic nature of the full
price elasticity, cigarette taxes could serve as an effective revenue
generating mechanism for states as well.
The elasticities in the first two columns range from -0.21 to -0.06
on the intensive and extensive margins and -0.44 to -0.33 on the full
margin. They are generally consistent in magnitude and sign with other
studies using individual consumption data with fixed effects (Farrelly
et al., 2001; Farrelly and Bray, 1998; Coleman and Remler, 2004). In all
three panels of Table 7, a comparison of the first two columns with the
last four columns illustrates ignoring geographic variability causes one
to overstate the home state price elasticity and understate the full
price elasticity in absolute value, though the "naive"
elasticity estimates are often quite close to, and are not statistically
different from, the full price elasticities. (32) The implication of
this finding is ignoring smuggling incentives when using micro-data will
not produce large biases in estimates of the full price elasticity on
average. This is an interesting result as there is no reason to believe,
a priori, that the bias in the full price elasticity will be small.
Further, omitting smuggling incentives from cigarette demand models will
preclude one from estimating the home state price elasticity, which is
arguably the more important parameter from a state tax policy
perspective as it yields the actual effect of a tax increase on
consumption in a given state rather than the potential effect absent
smuggling.
Smoking Increases, Casual Smuggling Percentages, and Net Sales
Effects
Because cross-state price differentials offer consumers access to
lower-priced cigarettes, casual smuggling can increase cigarette
consumption. I calculate smoking increases due to the effective price
reduction from smuggling by comparing the predicted value from each
regression to the predicted value from a counterfactual in which there
is no casual smuggling. This counterfactual is constructed by setting
the price difference equal to zero. More explicitly
[9] Percent Change in Q
E[Q | [P.sub.h] = [p.sub.h], [P.sub.b] = [p.sub.b]]] - E[Q |
[P.sub.h] = [P.sub.b]]/ E[Q | [P.sub.h] = [p.sub.h], [P.sub.b] =
[P.sub.b]].
Due to the functional form of the demand function, the preceding
expression can be negative for those who live very far from the border.
To correct for this problem, I set the percent change equal to zero if
it is negative. Note this adjustment produces similar results to
constraining the home state price elasticity to be weakly greater than
the full price elasticity: those who live far from lower-price borders
are assumed not to smuggle. The third row of each panel in Table 7
contains estimates of the percent increase in smoking due to smuggling.
Cross-border purchases increase consumption between 1.2 and 2.5 percent
on the intensive margin and between 4.0 and 8.2 percent for the full
model. Further, the availability of cheaper cigarettes increases the
smoking participation rate by 2.0 to 4.3 percent.
The demand model given by equation [6] also allows me to calculate
the proportion of individuals who purchase cigarettes in border
localities in a given MSA. I assume if everyone lived directly on the
border, no one would purchase in the higher-price state. Comparing
consumption for such individuals with consumption for those who do not
live close to the border yields the percentage of consumers who smuggle:
[10] Smuggling Percentage =
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