I was going through the report "ASSOCHAM Placement pattern study" and in that report it categorizes cities into various tiers. I wonder how it does that. It does not seem like it is done based on population. Following are some excerpts from that report.

SAMPLE SIZE
The study has covered employment trends across 33 prominent sectors located in 6 tier-I, 17 tier-II cities and 33 tier-III cities.

Tier I cities:
Among the tier I cities Delhi NCR and Mumbai recorded highest share in job creation with 34.06 per cent and 13.48 per cent share in total job creation respectively, during April to October 2009-10. But as compared to the April to October 2008-09, Delhi NCR registered 23.42 per cent decline in job creation whereas Mumbai registered 3.28 per cent
growth in job creation.

Employment scenario in Tier I cities (April – October 2009-10)
Tier I cities Share in %age Growth in %age as compare to the 2008-09
Delhi NCR 34.06 -23.42
Mumbai 13.48 3.28
Bangalore 10.70 -18.48
Chennai 5.59 -11.25
Hyderabad 5.36 19.33
Kolkata 4.27 64.82

Other tier I cities such as Bangalore, Chennai, Hyderabad and Kolkata registered 10.07 per cent, 5.59 per cent, 5.36 per cent and 4.27 per cent share in total job creation respectively, during April to October, 2009-10. But as compared to the April to October 2008-09, Kolkata and Hyderabad registered 64.82 per cent and 19.33 per cent growth in job creation, whereas Bangalore and Chennai registered 18.48 per cent and 11.25 per cent decline in job creation respectively.

Tier II cities
As per the analysis, 17 major tier II cities recorded 18.82 per cent share in total employment generation during April to October 2009-10. Among the tier II cities, Pune and Ahmedabad recorded 5.46 per cent and 5.01 per cent share in total job creation respectively, and registered 6.29 per cent and 21.50 per cent growth in job creation as compared to same period of last year.

Top five Tier II job creating cities (April – October 2009-10)
Tier II cities Share in %age Growth in %age as compare to the 2008-09
Pune 5.46 6.29
Ahmedabad 5.01 21.50
Chandigarh 1.95 21.58
Surat 1.13 137.02
Lucknow 0.82 0.82

Among the other major tier II cities Chandigarh, Surat, Lucknow and Gandhi Nagar recorded 1.95 per cent, 1.13 per cent, 0.82 per cent and 0.80 per cent share in total job creation during April to October 2009-10 and registered 21.58 per cent, 137.02 per cent, 92.66 per cent and 38.48 per cent growth in employment generation over the same period of last year.

Other tier II cities which had major share in employment generation during April to October 2009-10 were Jaipur (0.68 per cent), Vishakapatnam (0.50 per cent), Patna (0.41 per cent), Indore (0.33 per cent), Nagpur (0.32 per cent), Cochin (0.32 per cent), Ludhiana (0.28 per cent), Bhubaneswar (0.25 per cent), Bhopal (0.21 per cent), Amritsar (0.18 per cent) and Gwalior (0.17 per cent).

Tier II cities, which registered major growth in job creation during April to October 2009-10 as compare to the same period of 2008-09 were Vishakapatnam (115.21 per cent), Indore (60.00 per cent), Bhubaneswar (49.49 per cent), Jaipur (28.74 per cent) and Patna (20.52 per cent) whereas Bhopal, Amritsar, Gwalior and Ludhiana were among the cities which registered decline in job creation by 26.68 per cent, 9.60 per cent, 6.27 per cent and 3.94 per cent respectively.

Tier III cities
The impact of stimulus package provided by the government during the economic downturn generated majority of jobs in tier I and tier II cities, but the tier III cities were largely untouched, this would increase the migration of the unemployed people from small towns to cities. The analysis of the tier III cities shows that 21 cities out of 33 cities registered decline in job creation during April to October 2009-10 as compared to the same period of the last year. The 33 major tier III cities accounted for 7.70 per cent share in total employment generation during the period.

Top ten Tier III job creating cities (April – October 2009-10)
Tier III cities Share in %age Growth in %age as compare to the 2008-09
Vadodra 1.02 14.55
Pondicherry 0.58 -27.16
Ankleshwar 0.56 1.31
Vijayawada 0.46 -8.3
Guwahati 0.37 22.6
Dehradun 0.32 51.07
Aurangabad 0.31 -2.38
Coimbatore 0.31 -56.30
Kanpur 0.31 -75.78
Raipur 0.29 2.22

Among the tier III cities, Vadodra, Pondicherry and Ankleshwar recorded highest share with 1.02 per cent, 0.58 per cent and 0.56 per cent during the period respectively. As compared to the same period of last year, Ankleshwar and Vadodra registered 14.55 per cent and 1.31 per cent growth, whereas Pondicherry registered 27.18 per cent decline in job creation.

Other tier III cities, which registered major growth in job creation during April to October 2009-10 as compared to the same period of 2008-09 were Cuttack (99.05 per cent), Ranchi (54.86 per cent), Mysore (38.31 per cent), Calicut (26.92 per cent), Allahabad (1.58 per cent), Vellore (1.33 per cent) and Panjim (0.52 per cent).

If Tiers are based on population, then some of the anomalies in the above are Kanpur being labeled as a Tier III, Gandhi Nagar (separate from Ahmedabad) being labeled as a Tier II city, and having Bhubaneswar and Chandigarh in the same tier as Pune and Ahmedabad.