O had 2 questions regarding the Occasional Paper on "Key Household Income Trends, 2006" released by the Department of Statistics on 12 February 2007. I posed them to the DOS (albeit rephrased), and the DOS' responses (verbatim, without edits) are below.
O's question #1:
From the paper posted on the SingStat website, the definition of "employeed househould" is "households with at least one working person". This is somewhat ambiguous. If one member of a household has occasional or seasonal work that is less than a full year, then are they counted? If not, then the lowest quintile is likely overstated.
Data in DOS's Occasional Paper are obtained from household-based surveys conducted around the middle of the year. In the surveys, a person is classified as "working" if he/she worked for pay or profit during the reference week (ie the last seven days prior to the day of enumeration). Persons who had a job or business to return to but were temporarily absent because of illness, injury, breakdown of machinary at the workplace, labour management dispute or other reasons would also be classified as working. The statistical definition of "working persons" used in the surveys is in accordance with international statistical standards.
For persons who have only occasional or seasonal work that is less than a full year, and reported that they worked for pay or profit during the reference week during the household survey, they would be classified as" working".
O's question #2:
Are annual bonuses included on a pro rata basis in the monthly income? If not, the highest quintile is likely understated and the Gini coefficient is less sensitive than it should be to the economic cycle.
Monthly household income from work refers to the sum of monthly income received by all members of the household (excluding servants) from employment and business, inclusive of one-twelfth of the annual bonuses received in the last 12 months.