Historical test

The study constructed the SDM of LTCI financing through the dimensional consistency test, the structure test, and the historical test. According to the availability of data, the historical test simulation data select the number of urban employees insured by the SMI in demographic factors and the per capita disposable income of urban residents in economic factors for comparative analysis with the data of urban employees insured by the SMI and per capita disposable income of urban residents in China Statistical Yearbook from 2011 to 2019. The test results are shown in Supplementary Table 3. The average errors between the actual data and the simulated data are 0.78 and −3.41% (both <10%), respectively. Within a reasonable range, it shows that the model has a high fitting degree, is effective, and is reasonable (29).