Internet data collection in the LFS Danish experiences

Paris, April 2010

Outline

• Background

• Preparations

• The pilot

• Going full-scale

• Quality?

• Further work

Background 1

• The Danish LFS has individuals as sampling unit

• Until 2010 household variables collected via proxy in final interview

• From Q1 2010 Denmark collects household variables as required by regulation no. 577/98

Background 2

• Grant given from Eurostat in 2008

• Initial work on differences between CATI- and CAWI-interviews

Preparations

• Discussions on collection modes:– How much CATI?– How many reminders?– Letter vs. phone reminders?

• Two parallel universes

The Pilot

• Two reference weeks as sample

• Two weeks interview period

• Two groups: Aldi vs. Irma– Aldi: baseline with no reminders– Irma: Two phone reminders and

optional CATI

Pilot – the results

• What was learned:– Reminder needed– 2nd reminder not necessary– CATI option needed

• Showed that a pilot was essential

Going full-scale

• Not a big problem

• Not possible to keep as separate universes – today one big survey.

Preliminary results Q1 2010

0%

10%

20%

30%

40%

50%

60%

Mon

day

1

Tue

sday

1

Wed

nesd

ay 1

Thu

rsda

y 1

Frid

ay 1

Sat

urda

y 1

Sun

day

1

Mon

day

2

Tue

sday

2

Wed

nesd

ay 2

Thu

rsda

y 2

Frid

ay 2

Sat

urda

y 2

Sun

day

2

RefWeek 1

RefWeek 2

RefWeek 3

RefWeek 4

RefWeek 5

RefWeek 6

RefWeek 7

RefWeek 8

RefWeek 9

RefWeek 10

Quality

• Accepted a possibly lower quality.

• Primary issues: NACE, ISCO

• Further study needed

• Setup test vs. quality test

Further work

• In-depth quality analysis

• Coding of NACE and ISCO

• Analysing the mode effects of CAWI in core-LFS

Thank you!

Paris, February 2010Sammy Lauritsen ssl@dst.dk