specifications. Assuming migrants arriving in the first and the second half of a decade are homogeneous with respect to ability, the coefficient for years since migration ( _β3_ ) provides the assimilation effect.<sup>28</sup> The assimilation effect is negative and significant in each specification. Since the dummy takes value 1 if an individual migrated in the second part of a decade, the negative sign indicates that, keeping other things constant, the more time migrant spends in the US, the higher the predicted level of performance. Thus, in accordance to previous literature, experience acquired on the US labor market is an important determinant of performance. The estimations show a different picture for the general work experience, measured by age and its quadratic: these variables are only significant for the 1985 arrival. The small magnitude of the coefficients and standard errors is due to the log specification of the occupation indices. Mirroring Table 3 from sub-section 3.2, the coefficients of the education dummies suggest that the higher the educational level, the higher the occupational placement index.

Figure 1 presents the 1990 ÔP by country for the hypothetical individual arriving in the US in 1985. The results suggest that entry level occupational placement of skilled male US immigrants varies greatly by country of origin. The highest level of performance is attained by migrants from developed countries while the lowest indices are prevalent among those from Latin American countries.<sup>29</sup> These patterns confirm Mattoo et al. (2008) which also find that country of origin attributes and selectivity factors explain a lot of the surprisingly wide heterogeneity in performance of individuals with the same nominal education levels.

To evaluate the progress within the ten years closest to migration, I plot ΔÔP between year 2000 and year 1990 versus the ÔP in 1990 for the 1980s arrival, as shown in Figure 2, and ΔÔP between year 1990 and year 1980 versus the ÔP in 1980, for the 1970s arrival in Figure 3a. The distribution of countries based on ÔP, which is represented on the X axis, depicts a more complete version of the picture presented in Figure 1 for selected countries and one period of arrival. Figures 2 and 3a show that there is improvement in the occupational placement within the decade closest to the arrival time, for skilled immigrants coming from various countries. Additionally, the negative correlation between the entry levels of occupational placement and the subsequent improvement seems to suggest the existence of convergence forces working to reduce the differences in performance levels among various countries. These patterns are robust to

> 28 If there is difference in immigrants’ ability between the two periods of arrival within a particular decade, then _β3_ captures cohort effects rather than assimilation.  In that case, the assimilation effect itself can not be identified at all because the 1980 and 1990 censuses do not provide information on the specific years of arrival.

> 29 For comparison, as of Census 1990, the weighted average occupational index calculated for all US-born skilled males (irrespective of wage or employment status) is about 77.

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