workshop lfs, april 15 2010 estimating the non-response bias using exogenous data on employment...

Workshop LFS, April 15 2010

Estimating the non-response bias using exogenous data on employment

Etienne Debauche

Corinne Prost


Response rate in the French LFS

›large variability in space and in time

›special event in 2007

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Response rate (seasonally adjusted)

Response rate (raw)



›non-response survey:

-« light » PAPI survey, sent to the non-respondents

-around 20% of the non-respondents answer to this survey

- they are more often employed than the respondents of the main survey

›question: is the correction of non-response in the weighting scheme efficient enough to correct for non-response bias?



›one study done in 2007: very small effect of the response rate on the measure of the unemployment rate

›geographical analysis

›problem: the response rate is endogenous: employment rate and response rate are both impacted by the business cycle


Employment in the French LFS

›Employment: differences between the LFS estimate and the official employment estimate, coming from administrative database

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LFS employment estimateAdministrative employment estimate


Employment in the French LFS

›a lot of reasons why both estimates are different:

-concepts: ILO employment / job statistics; differences for sick leaves, maternity or paternity leaves

-scope: total employment / private employment; frontier workers; collective households

-quarterly average / average of the number of jobs at the end of the quarters

›And errors in the LFS: sampling errors; non-response bias; bias due to the proxy answerings


Modeling the non-response rate

›behavior of the interviewers: they start with easier interviewees (for instance non-active ones). They stop when the cost of search exceeds the benefit.

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Using the administrative data employment estimates to assess the non-response bias

Response rate:

Administrative data employment:

LFS employment:

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Using the administrative data employment estimates to assess the non-response bias

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Using the administrative data employment estimates to assess the non-response bias›estimation at the region level (NUTS2 and NUTS3), with region and time fixed effects: the effect of the response rate is identified within the regions, independently of the national business cycle

›estimation on the employment rates

›weight: population of the region

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Effect of the response rate

Variable (1) (2) (3)Administrative employment rate 0,40 0,36 0,02

(0,13) (0,09) (0,01)LFS Response rate 0,31 0,09 0,06

(0,04) (0,03) (0,02)

Level France NUTS2 NUTS3Period 2003q1-2009q3 2003q1-2009q3 2003q1-2009q3

TABLE 1DEPENDENT VARIABLE: LFS EMPLOYMENT RATE

ESTIMATION WITH FIXED-EFFECTS



›robustness check thanks to the natural experiment of 2007: the increase of the response rate on 2007 is due to the controversy. It should be exogenous.

Variable (1) (2) (3) (4)Administrative employment rate 0,40 0,36 0,02 0,02

(0,13) (0,09) (0,01) (0,02)LFS Response rate 0,31 0,09 0,06 0,08

(0,04) (0,03) (0,02) (0,03)

Level France NUTS2 NUTS3 NUTS3Period 2003q1-2009q3 2003q1-2009q3 2003q1-2009q3 2006q1-2007q4

TABLE 2DEPENDENT VARIABLE: LFS EMPLOYMENT RATE

ESTIMATION WITH FIXED-EFFECTS



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LFS employment simulated LFS employmentadministrative employment


Conclusion

›There is a significant effect; can the correction for non-response be improved?

›The effect is not large. In particular, it only explains a small part of the discrepancies between LFS employment and administrative data employment. Can the other sources of discrepancies be quantified?


Discussion

›similar results in other countries?

›do some countries use external administrative data employment in the weighting scheme (grossing factor)?

workshop lfs, april 15 2010 estimating the non-response bias using exogenous data on employment...

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