Harris-Todaro Model: The model was formulated by John R. Harris and Michael P. Todaro. The model explains that accelerated rural-urban migration has led to increased urban unemployment.
The four basic elements of the model are:
(a) Rural-urban migration is influenced not only by economic but also by socio-psychological considerations.
(b) The migration depends on expected and not actual wage difference.
(c) The probability of finding a job in urban area is a function of urban employment rate.
(d) Excessive migration over and above top opportunity growth rate in urban areas is bound to create urban unemployment.

Implications of the Model
1.The government must develop strategies to create an appropriate rural-urban economic balance.
2.It is advisable that industries should use labour intensive techniques.
3.More labour absorbing industries should be settled.
4.It is important to eliminate the factor prices distortions.
5.Various capital subsidies must be removed to eliminate factor price distortions.
6. A developing country must introduce an effective education system that will be able to meet the needs of rural development and create employment for perspective job-holders.
7. It is important to control population so as to avoid unemployment in the economy
8. Local self government can play a positive role in minimizing the rural urban migration.

Relevance of the Model
(a) The model focuses on institutional determinants of urban wage rates.
(b) It also explains the high cost of labour turnover.
(c) High wage rates in urban areas enable urban employers to get high quality work force and greater productivity.