Understanding the evolution of employment in megacities is an exercise in both observation and inference. The broad narrative—manufacturing retreating, services advancing—may seem familiar, but it is the fine detail that truly matters to urban planners and labor economists. For those seeking to move beyond anecdotes and conventional wisdom, the ISIC framework, when applied at the municipal level, becomes a powerful instrument for tracing, mapping, and anticipating shifts in the urban labor market.
The starting point is municipal business registration data, where each entity is typically tagged with an ISIC code. For megacities with millions of residents and hundreds of thousands of registered firms, this data is more than a list; it is a living map of economic activity. Tracking the number of active registrations in manufacturing (ISIC 10–33) versus services (ISIC 45–99) over time can reveal not just headline trends but the contours of transition—whether the decline of manufacturing is slow and steady or marked by abrupt closures, and whether services growth is concentrated in retail, logistics, information, or professional activities.
The methodology is straightforward in outline, if sometimes tedious in execution. Compile business registration records for a series of years, ensuring that each record includes the appropriate ISIC code and, ideally, information about firm size, location, and employment. Aggregate the data by major ISIC sections: manufacturing (10–33), services (45–99), and, if desired, finer-grained categories within each. Year-over-year changes in the number and share of firms, especially those with significant employment, provide a window into economic restructuring.
Yet the value of such an exercise is greatest when mapped onto urban realities—housing, transport, and the lived experience of city residents. Shifts away from manufacturing often bring with them declines in industrial land use, sometimes freeing up space for residential or commercial redevelopment. The growth of service industries, especially those in the professional or information sectors, can alter patterns of demand for office space, change the geography of commutes, and drive up housing prices in particular neighborhoods.
To move from economic codes to planning insights, analysts should integrate business registration data with housing and transport demand indices. For housing, this may mean comparing the location and growth of service-sector firms to trends in residential construction permits, rent levels, or population inflows. A surge in registrations for IT or financial services firms in one district may be followed, after a lag, by rising demand for apartments, amenities, and schools in the same area.
Transport demand offers a parallel story. Manufacturing jobs, once clustered in peripheral zones or near ports and rail terminals, generate different patterns of mobility than service jobs concentrated in urban cores. By mapping changes in ISIC-coded employment against transport usage—whether measured by public transit ridership, road congestion, or new mobility services—urban planners can detect mismatches or emerging needs. For example, a rapid shift toward service employment in an area not well served by mass transit might prompt new investment in infrastructure or revised zoning policies.
The granularity of ISIC codes allows for targeted analysis. Not all services are created equal; a growth in hospitality or retail has different implications for daily commuting and housing than an uptick in legal or consulting firms. Tracking which specific service subcategories are expanding provides a more nuanced picture, one that can guide both public investment and private development.
It is worth acknowledging the limitations. Not all employment is captured in formal business registrations, particularly in the informal or gig economies that thrive in many megacities. Furthermore, changes in registration do not always translate immediately into shifts in actual employment or land use—firms may register in advance of growth, or maintain dormant registrations for years. Analysts should therefore combine business registration data with survey evidence, census data, and, where available, administrative records of employment and tax filings.
Still, even with these caveats, the ISIC-based approach provides a systematic and replicable methodology for understanding urban economic change. The discipline of coding, aggregation, and spatial mapping turns scattered registrations into actionable intelligence. Planners can anticipate where new housing or transport capacity will be needed, identify neighborhoods at risk of displacement or congestion, and align infrastructure investment with the evolving structure of the urban economy.
As megacities continue to grow and diversify, the need for clarity in economic analysis becomes only more pressing. ISIC codes, though sometimes viewed as a technical detail, are central to this clarity. They offer a language for describing change, a method for measuring it, and a foundation for policies that shape the urban future.