Two economists, Diego Comin and Martí Mestieri, noticed something odd about how technology travels. New inventions now arrive in lower-income countries almost as fast as in rich ones; how deeply they end up used keeps drifting apart. Arrival converged, depth diverged, and that quiet asymmetry explains a surprising share of why incomes haven't. I wanted to see it with my own eyes, so I timed seven technologies, from the fixed telephone to the electric car, across every country with data: how long each took to arrive, and how long to actually matter.
Worth noticing: the collapse is dramatic. A low-income country waited a median 41 years for the fixed telephone, 20 for the internet, 15 for broadband. For solar power the wait is 6 years, exactly the same as in high-income countries. Technologies that come in modular units you can buy by the container, rather than networks you must build, now arrive almost everywhere almost at once.
Worth noticing: arrival is only half the story. High-income countries went from 5% to 50% internet use in a median 8 years; no low-income country has crossed 50% yet, so they don't appear in that bar at all; the divergence hides in what's missing. The exception is solar, where latecomers deepen faster than pioneers (3 to 4 years from 1% to 10% of generation, versus 9 in high-income countries): once a technology is cheap and modular, depth follows arrival quickly.
Each point is one country × one technology. Horizontal: years the technology took to arrive (extensive lag). Vertical: years from arrival to intensive use (intensive lag). Colours are World Bank income groups. The cloud compresses left to right over successive technologies (arrival has converged) while the vertical spread persists: deepening has not.
Worth noticing: squint and this is Comin and Mestieri's whole argument in one cloud. Newer technologies pile up against the left edge, meaning arrival has converged, while the vertical spread refuses to shrink: deepening has not. And the dots that are missing matter as much as the ones plotted; countries that never reached the intensive milestone don't appear here at all.
Adoption trajectories for all countries with data, coloured by income group. Dashed horizontal lines mark the three milestones used in this tracker.
Try this: select mobile: 203 of 214 countries have passed 50 subscriptions per 100 people, the fastest and most complete diffusion in the data, achieved by leapfrogging the fixed-line network rather than extending it. Then select electric cars: still a rich- and middle-income story, with no low-income country in the data past even the 1% mark.
When each technology reached this country's three milestones. Open circles are left-censored: the country was already past the milestone when the data series begins, so the true crossing year is earlier.
Try this: policy can compress these timelines dramatically. Norway took electric cars from 1% to 25% of new sales in five years; Chile took solar from 1% to 10% of its electricity in six. When the technology is ready and the incentives line up, “intensive use” can arrive within a single government's term.
This page puts fresh, still-maintained open data under a known result: Comin and Hobijn's CHAT dataset tradition and Comin and Mestieri (2014), “If Technology Has Arrived Everywhere, Why Has Income Diverged?” (AEJ: Macro). It builds no index, ranks no one, and claims no causal effects. It just makes the pattern visible.
For each technology × country, the tracker records the first year the adoption series crosses three thresholds. Thresholds are technology-specific, because a sensible “intensive use” level for solar's share of electricity is not the same as for mobile subscriptions:
Extensive lag = country's first-milestone year minus the global pioneer's first-milestone year (the earliest crossing observed in the data). Intensive lag = country's third-milestone year minus its own first-milestone year.
If a country is already past a milestone in the first year its series is observed, the crossing is left-censored: the true year is earlier than the data can show. Censored observations are marked with open circles in the country view and are excluded from all median-lag statistics rather than guessed. This mainly affects the fixed telephone (series start 1960) and electricity access (series start 1990) for early adopters. Survivor bias runs the other way for recent technologies: intensive-lag medians only include countries that have already reached intensive use, so they understate the true divergence.