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Make or Buy Urban Public Transport Services: A Rational Choice?

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Considering the quality of the data available and the variety of provision modes,<br />

we decided to go a step further in the analysis of the determinants of <strong>or</strong>ganisational<br />

choices and we proceeded to an estimation assuming that the variable Organization i<br />

is a qualitative variable, not an <strong>or</strong>dered one. The <strong>or</strong>dered logit specication includes<br />

indeed several restrictions 14 . One imp<strong>or</strong>tant is that the unobserved fact<strong>or</strong>s (ɛ i ) that<br />

tend to shift <strong>or</strong>ganizational choices from direct provision to semi-public contracting<br />

also inuence the shift from semi-public contracting toward private contracting. This<br />

is not the case in a multinomial logit model where unobserved fact<strong>or</strong>s are assumed to<br />

be unc<strong>or</strong>related. In this model, the probability that the local auh<strong>or</strong>ity i provides the<br />

service through mode j is given by :<br />

P r {Organization i = j} = exp(X iβ j )<br />

∑ 3l=1<br />

, j = 1, 2, 3. (3)<br />

exp(X i β l )<br />

where X i is a vect<strong>or</strong> of economic and non-monetary determinants of service provision<br />

choices. The results based on this specication are provided in columns 2 and 4 of<br />

table 3. Not only do these results conrm our central propositions regarding the economic<br />

motives of <strong>or</strong>ganisational choices but they also provide m<strong>or</strong>e precision on the<br />

eect of each variable on the choice of arrangements open to local auth<strong>or</strong>ities. Indeed,<br />

models 2 and 4 indicate that an increase in service complexity is associated with a shift<br />

away from private contracting toward in-house provision but not toward semi-public<br />

contracting. Similarly, Uncertainty i and Size i appear as explanat<strong>or</strong>y variables of<br />

the trade-o between in-house provision and private outsourcing but do not intervene<br />

in the trade-o between semi-public outsourcing and private outsourcing. At last,<br />

Cities i is found to be a signicant determinant in model 3 but not in model 4, which<br />

suggests that the number of cities covered by a netw<strong>or</strong>k is only a determinant of the<br />

shift away from semi-public contracting to in-house provision.<br />

In the end, what these estimates reveal is that the trade-o between in-house provision<br />

and private outsourcing is dictated by economic fact<strong>or</strong>s such as the level of<br />

complexity of the service, the degree of demand uncertainty and the potential f<strong>or</strong><br />

competition. But these variables do not explain the choice of semi-public contracting.<br />

Impact of non-monetary determinants. Results of our estimates indicate that<br />

the rate of unemployment of a city is not a signicant determinant of the <strong>or</strong>ganizational<br />

choices made by its local government regarding urban transp<strong>or</strong>t. A possible<br />

explanation is that legislation f<strong>or</strong> utilities industries does not give private operat<strong>or</strong>s<br />

a large room of leeway as regards their number of employees. Theref<strong>or</strong>e, private outsourcing<br />

may not be considered as threatening the level of employment in the transp<strong>or</strong>t<br />

14 The err<strong>or</strong> in applying an <strong>or</strong>dered model to a non-<strong>or</strong>dered variable is much higher than the converse<br />

(Maddala 1983).<br />

20

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