Table 3 OLS, IV 2SLS and Control Function Approach Parameter Estimates of impact of Health Insurance on Health Status (Dependent variable = Mortality)
From: The impact of health insurance enrollment on health outcomes in Kenya
| Â | OLS | Reduced Form Estimates for Health Insurance Status in IV 2SLS | IV 2SLS | Control function approach |
|---|---|---|---|---|
Health Insurance status | 0.010 (-0.009-0.030) | Â | -0.048* (-0.103-0.007) | -0.027 (-0.068-0.014) |
Out of pocket expenditure in KES | 0.00001 (-0.0001-0.0001) | 0.0004*** (0.0001-0.0006) | 0.00003 (-0.0001-0.0002) | 0.00002 (-0.0001-0.0002) |
Proportion with health insurance per cluster | Â | 0.967*** (0.886-1.047) | Â | Â |
Age in years | -0.0003 (-0.001-0.001) | 0.001* (-0.000-0.003) | -0.0002 (-0.0012-0.0008) | -0.0002 (-0.001-0.0008) |
Age groups [Reference: early and late childhood] | ||||
 Adolescence & youth | 0.006 (-0.030-0.043) | 0.036 (-0.072-0.145) | -0.008 (-0.079-0.064) | 0.004 (-0.036-0.044) |
 Adults | 0.003 (-0.042-0.049) | -0.050 (-0.137-0.038) | -0.004 (-0.062-0.054) | 0.004 (-0.046-0.053) |
 Elderly | 0.008 (-0.057-0.073) | -0.012 (-0.072-0.048) | -0.004 (-0.044-0.036) | 0.007 (-0.064-0.078) |
 Male gender | 0.002 (-0.013-0.017) | -0.009 (-0.035-0.017) | 0.006 (-0.011-0.023) | 0.006 (-0.011-0.023) |
Marital status [Reference: Married] | ||||
 Special single | 0.077*** (0.054-0.017) | -0752*** (-0.113- -0.037) | 0.078*** (0.052-0.103) | 0.079*** (0.054-0.104) |
 Single | 0.004 (-0.017-0.026) | -0.035* (-0.072-0.002) | 0.0010 (-0.024-0.025) | 0.0014 (-0.023-0.026) |
Religion [Reference: Christian] | ||||
 Muslim | 0.0005 (-0.032-0.033) | -0.050 (-0.108-0.008) | 0.004 (-0.034-0.042) | 0.005 (-0.033-0.042) |
 Hindu and others | 0.033 (-0.021-0.087) | -0.086* (-0.179-0.007) | 0.020 (-0.041-0.081) | 0.021 (-0.039-0.083) |
Education [Reference: None] | ||||
 Primary | -0.13 (-0.032-0.006) | 0.044*** (0.012-0.075) | -0.108 (-0.031-0.010) | -0.011 (-0.032-0.009) |
 Secondary and higher | -0.016 (-0.038-0.006) | 0.102*** (0.065-0.140) | -0.007 (-0.033-0.019) | -0.009 (-0.034-0.017) |
 Media exposure | -0.009-0.029-0.010) | 0.109*** (0.075-0.142) | -0.002 (-0.026-0.021) | -0.004 (-0.027-0.018) |
Main source of energy for cooking [Reference: Wood-based] | ||||
 Electricity | -0.032 (-0.124-0.059) | 0.026 (-0.142-0.195) | -0.029-0.141-0.083) | -0.032 (-0.143-0.080) |
 LPG gas | -0.012-0.0408-0.016) | 0.084*** (0.029-0.140) | -0.001 (-0.038-0.036) | -0.003 (-0.039-0.034) |
Drinking water access type [Reference: Piped or bottled water] | ||||
 Spring water | 0.009 (-0.009-0.029) | 0.040** (0.009-0.073) | 0.006 (-0.014-0.027) | 0.006 (-0.014-0.027) |
 Rain and surface water | 0.018 (-0.004-0.029) | 0.050*** (0.016-0.085) | 0.019 (-0.004-0.042) | 0.018 (-0.004-0.041) |
 Vendors water | 0.016-0.024-0.057) | 0.019-0.046-0.084) | 0.017 (-0.026-0.060) | 0.017 (-0.026-0.060) |
 Others | 0.032 (-0.036-0.101) | 0.106*-0.005-0.218) | 0.019 (-0.055-0.093) | 0.018 (-0.056-0.092) |
 Rural residence | -0.006 (-0.022-0.011) | 0.079*** (0.049-0.108) | -0.003 (-0.021-0.016) | -0.003 (-0.021-0.015) |
 Household size | 0.004** (0.000-0.008) | 0.012*** (0.005-0.018) | 0.004* (-0.000-0.008) | 0.004* (-0.000-0.008) |
Employment status [Reference: Formal] | ||||
 Informal | -0.001 (-0.019-0.018) | -0.111*** (-0.143- -0.079) | -0.010 (-0.032-0.012) | -0.009 (-0.030-0.013) |
 Not working | -0.009 (-0.032-0.014) | -0.074*** (-0.112- -0.035) | -0.015 (-0.041-0.010) | -0.014 (-0.040-0.011) |
Income quintile [Reference: Poorest] | ||||
 Poor-middle | 0.007 (-0.021-0.037) | 0.006 (-0.040-0.053) | 0.006 (-0.023-0.038) | 0.007 (-0.024-0.038) |
 Middle | 0.002 (-0.026-0.037) | 0.062** (0.015-0.108) | 0.007 (-0.023-0.038) | 0.006 (-0.024-0.038) |
 Middle-rich | 0.009 (-0.019-0.039) | 0.075*** (0.028-0.122) | 0.010 (-0.022-0.042) | 0.0009 (-0.023-0.041) |
 Richest | 0.007 (-0.024-0.040) | 0.128*** (0.076-0.180) | -0.014 (-0.022-0.049) | -0.012 (-0.023-0.047) |
Distance to water source-time in Minutes | Â | -0.0001 (-0.0005-0.0002) | Â | Â |
Distance to nearest tar/asphalt road in Kilometers | Â | 0.0002 (-0.0003-0.0007) | Â | Â |
Distance to nearest bus/matatu stage in Kilometers | Â | 0.0007 (-0.001-0.003) | Â | Â |
Distance to nearest market in Kilometers | Â | 0.00002-0.001-0.001) | Â | Â |
Distance to nearest public primary school in Kilometres | Â | -0.002 (-0.009-0.006) | Â | Â |
Distance to nearest public secondary school in Kilometers | Â | 0.0006 (-0.001-0.002) | Â | Â |
Distance to nearest health facility in Kilometers | Â | -0.003 (-0.007-0.001)) | Â | Â |
Health insurance status residuals | Â | Â | Â | 0.026* (-0.001-0.053) |
Health insurance status X its residual | Â | Â | Â | -0.013 (-0.042-0.016) |
Constant | 0.025 (-0.032-0.083) | -0.102* (-0.256-0.012) | 0.042 (-0.044-0.127) | 0.035 (-0.027-0.098) |
Diagnostic tests | ||||
 R2 for the regression | 0.023 | 0.323 | 0.014 | 0.025 |
 Durbin |  |  | 5.39** |  |
 Wu-Hausman |  |  | 5.34** |  |
 Adjusted R2 |  |  | 0.315 |  |
 Partial R2 |  |  | 0.171 |  |
 Shea’s Partial R2 (>1 endogenous variable) |  |  | 0.171 |  |
 Adjusted partial R2 |  |  | 0.157 |  |
 First Stage F-statistic [joint significance of instruments] |  |  | 71.09*** |  |
 Minimum eigenvalue statistic (Cragg & Donald: similar to First stage F in case of one endogenous variable) |  |  | 71.09 |  |
 Sargan’s tests statistic |  |  | 6.18 |  |
 Basman tests statistic |  |  | 6.11 |  |
 Health insurance status residuals F-test |  |  |  | 3.50* |
 Health insurance status X its residual F-test |  |  |  | 0.73 |
 Observations | 3,175 | 2,790 | 2,790 | 2,789 |