But there were also other structural changes in the economy over this time period. Some of these trends may have contributed to higher participation in alternative work arrangements. As enumerated by Katz and Krueger, these include technological advances that have made contingent work easier, an aging workforce more likely to be self-employed, and a fissuring of the workplace. Other secular trends may have slowed down the growth of contingent work, including a slowdown in business starts and decreasing employment among small firms. In other words, teasing out whether the contingent workforce grew or shrank relative to what would have been expected if not for these contextual factors is like tracking a feather in a hurricane.
3. Measuring growth in contingent work requires comparability between data points over time, which is difficult to achieve given differences in definitions, sources of data, and samples.
Survey data, such as the CWS, show that contingent work is stable. However, as mentioned above, evidence from tax records suggest that an increasing percent of tax filers are earning income from alternative work arrangements. Our own research measuring the percent of adults participating in the Online Platform Economy is more consistent with tax data, showing growth in contingent work.
The difficulty of measuring growth is exacerbated by respondents' varying interpretations of a survey question which can also change depending on context. A recent paper linking household survey respondents to tax filing data illustrates just how inconsistently people respond in different data sources: just 35 percent of respondents who filed the self-employment (SE) schedule on their taxes reported in the CPS that they are self-employed. Importantly, this discrepancy is increasing. This implies that, despite recent estimates of stability released by the CWS, they are not the last word on the levels and trends of contingent work, and administrative data help triangulate the picture.
Our own experience measuring the percent of adults participating in the Online Platform Economy highlights the difficulty in keeping a pulse on this dynamic sector. We sized the Online Platform Economy based on inflows into consumer checking accounts from labor and capital platforms. We started with a list of 30 platforms in our estimates as of October 2015. For the estimates we released for June 2016, just eight months later, we had expanded the set of platforms to 42. Later this year the JPMorgan Chase Institute plans to publish new estimates on participation in the Online Platform Economy through mid-2018, and our list has exploded to over 100 platforms. Importantly, some of this growth may reflect the migration of previously existing forms of contingent work on to online platforms and not necessarily net new growth in alternative work arrangements. We look forward to exploring these questions and sharing our results.