5 distribution, because, in most countries, that is generally where rents are either captured by the operator or shared with users. More specifically, we measured PPI in the sector by the year private parties started to participate in asset ownership, capital investment, commercial risk, and/or operation and maintenance in electricity distribution.

For telecoms, we rely on the definition used by the International Telecommunications Union (ITU). According to ITU, PPI refers to full or partial private ownership of the assets of fixed-line telephone companies. We focus on fixed-line telephony because in most countries the private sector is active in mobile telephony. This is equivalent to having PPI in all countries, which would be much less interesting as an econometric variable. The degree of PPI in fixed telephone companies is an indication of the extent to which the public sector has been willing or able to rely on private financing for the expansion of fixed-line services. In Africa, for instance, PPI is found in fixed telephony in just 50 percent of countries. In water, PPI refers to asset ownership or capital investment. It ignores management contracts, which involve private management rather than capital.

With these definitions and issues in mind, we began to collect data from various sources, relying on a Web search and commercial databases to get a first impression of the situation. For telecoms, the information was relatively easy to collect, thanks to the ITU database. For water and for electricity, however, the information was partial and sometimes inconsistent across sources. We then prepared a questionnaire which we sent to colleagues in international organizations directly involved in the reforms of these sectors across the developing world. Their responses helped us to reduce the inconsistencies. When necessary, we contacted the relevant country authorities to settle uncertainties or disagreements across sources. The data samples vary across sectors because, in spite of our consultations with the key actors, we were not able to obtain for electricity and water the same coverage that ITU has managed to generate for telecoms. Our country coverage ranges from 120 to 153, depending on the indicator and the sector. This is still quite a significant advance over prior publications in electricity and water.<sup>14</sup> The information we collected on the spread of IRAs and PPI between 1990 and 2004 is summarized in Table 1. The baseline (1990) reveals a distinct preference around the world for self-regulated public provision. Since then, the share of countries with an IRA and PPI has swelled in all sectors. But some sectors have seen their ownership and institutional structure change much more than others.

Table 1 also reports the information we collected on the timing of the reforms in the three sectors covered. On average the reforms began at roughly the same for the three sectors. The average start was around 1998, with the water sector lagging by a year. Contrary to what is viewed today as best practice, most countries established their IRA shortly after opening their telecoms and water sectors to private participation. Our data panel covers, on average, about five years of experience with reform. For some countries, of course, the coverage is much longer. Argentina, for example, commenced reforms in all three sectors between 1991 and 1993.

14 For more details about the data-gathering process see Estache and Goicoechea (2005).