represent more than 75 percent of the aggregate dollar value of 2007 exports (or ~USD 700 million). By default, 100 percent of the 2006 FPDs are continued because of the way the data is arranged: the data is left-censored so we do not know if any of the firms had been active in 2005.

**Figure 7:** Intensive and extensive export margins by number of units (left) and USD value (right); each year, every FPD unit is classified in one of four mutually exclusive groups: new destination (units from old firm, with old product, to new destination), new product (units from old firm, with new product), new firms (all units from firms with no prior exports) and cont‟d (all other units). At the top of each bar is the percentage of that year‟s number of FPDs (left) or USD value (right) that each category takes up.

<!-- Start of picture text --> 2000 1200mil.$<br>74.4% 96.9%<br>65.1%<br>1600<br>800mil.$ 75.2%<br>1200<br>100.0% 100.0%<br>800<br>46.3%<br>41.2% 18.5% 400mil.$<br>17.2% 75.8%<br>13.9% 20.6%<br>400<br>10.2% 7.7% 22.9% 1.9%<br>2.3% 2.4% 0.7% 0.2% 1.1% 3.9% 1.2%<br>0 0mil.$ 0.3% 0.0%<br>2006 2007 2008 2009 2006 2007 2008 2009<br>cont'd cont'd new dest new firm new prod cont'd new dest new firm new prod cont'd new dest new firm new prod cont'd cont'd new dest new firm new prod cont'd new dest new firm new prod cont'd new dest new firm new prod<br><!-- End of picture text --> _Source:_ Authors‟ calculation based on Lao PDR Customs data What we see in the two tables is that there is a considerable amount of experimentation: some 25-60 percent of FPDs in any one year are _new_ , and 2007 appears to have been particularly active. On the dollar value side, however, the incumbents dominate by far, accounting for some 75-97 percent of the value in the three years. This is consistent with the findings of Cadot et al. (2010) on African countries, as well as the conclusions of Brenton and Newfarmer (2007) on the importance of the intensive margin in explaining export growth in developing countries.

This simple demonstration of the fact that exploration and export discovery, even if actively encouraged, account for little of the export value presages the survival analysis which will be presented in section 4. It also illustrates the need to support exporters beyond the exploration phase of their activity (the sustainability margin) in order to have any significant value impact from this exploration (the intensive margin).

# **_3.3 Survival Statistics_**

As mentioned in the introduction, after the seminal work of Besedes and Prusa (2006), several other papers have confirmed the finding that the median duration of export spells in developing countries is very short, typically two to three years. We investigate this aspect in the Lao data and present a simple view of the spell duration in Table 4 for each of the elements of the export space (firms, products and destinations as well as combinations). To do this, we disregard left and right censoring as well as gaps (absences during one or two years) and instead focus on the number of years that a unit is present in the data during the period of full coverage (2006-2009).

_Exporting from a small landlocked economy_ _12_