A former head of the Bureau of Statistics has told a Senate inquiry he considered not putting his name on this year's census form, knowing the bureau had no power to compel him to do so.
Bill McLennan said when he was in charge of the bureau in the 1980s and 1990s he reviewed legal advice that said it had no power to demand names in conducting its surveys, because names were not required for "statistical purposes" under the Census and Statistics Act.
Mr McLennan is giving evidence alongside representatives from the bureau's information technology contractor, IBM, and the Prime Minister's special adviser on cyber security.
"I am sure it is not legal to collect names compulsorily," he told the hearing.
He said that after much thought he did provide his name, but left off his date of birth, providing his age instead.
The legal advice, provided by parliamentary counsel and seen by Fairfax Media, says the ABS can only compel the provision of information for statistical purposes.
Names collected by the ABS are used for administrative rather than statistical purposes, as they are not published in tables of statistics.
"Under those circumstances, I think it would be a gross injustice to have people prosecuted and fined," Mr McLennan said. "That's a personal opinion."
Leaving off names would not compromise the census, but demanding names might, because if people filling out the census were miffed about having to give names they might "botch a few questions deliberately".
"That could easily happen, and nobody would know, and that would affect quality," he said. "But I don't know that's happened. I couldn't tell you whether it did or not. Even the post-enumeration survey wouldn't pick that up.
"You would need a door-to-door survey asking 'did you give the correct answers' to the questions to pick that up."
IBM Australia managing director Kerry Purcell confirmed the census website suffered four denial of service attacks on census day, Tuesday, August 9, at 10.10am, 11.45am, 4.50pm and 7.27pm, which he likened to "parking a car across a driveway". Most of the attacks came from Singapore.
When IBM attempted to shield the site from overseas traffic under a protocol known as Island Australia, one of its internet service providers failed to do so, despite earlier assurances that it could.
IBM was prepared to put the site back on line at 11.30pm, four hours after it took it took it down at 7.33pm, but the Bureau of Statistics decided to wait for what turned out to be another 39 hours, until 1.35pm on Thursday, August 11.
It has offered to pay the ABS for the extra costs incurred on census night and is negotiating a "commercial settlement" with treasury secretary John Fraser.
No IBM staff have been dismissed or disciplined as a result of the census outage.
A representative from Capability Driven Acquisition, which advised the ABS on selecting IBM, told the committee several other potential bidders believed there was little point in competing against IBM because it would win the contract.
