Angrist & Kugler(2003)研究发现，欧盟国家短期内对劳动力流动自由弹性的降低会保护本国劳动力，但长期来看，移民劳动力的负面影响会增加，冲击均衡就业的概念。因此，就保护原住民而言，短期需求可能是有利可图的，但从长期来看，当技能、收入和生活方式的差距将显著扩大时，这可能是有害的。考虑到与小规模工业相比，长期劳动力需求在很大程度上更为稳定，主要的差别在于工资和技能。如果他们被区别对待，被排除在进步和学习之外，那么这两者之间的工资差距将对他们更具侮辱性，而技能差异则会影响他们的生产率和产出。
Secondly, it is also possible to avoid such situations by introducing a standardised training program for all workers at same level, and equip the native labours with the necessary skills to uplift them to the skills possessed by the immigrants and the immigrants to even higher level of skills. This will maintain harmony among the two and consistent progress will eventually test the personal abilities of the workers. The short term labour demand is originated largely from the small scale industries who are excluded from the mainstream large scale industries which are primarily capital intensive, attracts skilled and unskilled labours, and has a long sight in terms of perpetual development of the organisation. The short term demand will probably create a hypothetical demand for skilled labours and immigrants will be welcomed for the short haul being disrespectful of the fact that the short term demand generated will eventually end up in joblessness or degradation of wages when migrating to large scale industries. This is because large scale industries are embedded with policy impositions of mandatory support provision for native workers resulting into a gradual development of wages, equal treatment to all immigrants and native, and also standardizing the product ion practices thereby reducing the disparity in skills.
Angrist & Kugler(2003) have researched that reduced flexibility in the EU nations about the freedom on labour mobility for a short term will protect the native labours, but in the long term the negative impacts of immigrant labours will increase and hit the concept of equilibrium employment. Thus, the short term demand may be lucrative in terms of protecting the natives, but it may be harmful on the long term when the disparity of skills, income, and lifestyle will significantly increase. Considering the long term labour demand which is largely more constant compared with the small scale industries, the prime differentiator is wages and skills. The wage difference between the two will be more insulting to the native if they are treated differentially and excluded from progressing and learning, whereas the skill difference will hit their productivity and output.