Questions about the capacity of Statistics SA to deliver data of consistent quality have been raised on a number of occasions recently.
Any assessment of organisational capacity must take account of at least two elements: quantity (the number of people retained to undertake the various activities that, when combined in the best possible manner, constitute the overall output of the institution); and quality (the qualifications, competence, knowledge and experience of those retained to do the job).
Stats SA has capacity constraints in both these areas.
Given the frequency and number of its statistical outputs, and the complexity of the data collection and dissemination cycle, it is understaffed.
In addition, there was a break with the past in 1994, when government departments redefined their roles and priorities, and began restaffing to reflect new policy and operational priorities (including increasing, as rapidly as possible, the representation of those historically disadvantaged and excluded from statistical production).
This had the necessary consequence of breaking continuity in terms of experience and institutional knowledge, with people less experienced having to learn rapidly "on the job" rather than following a leisurely and predictable progression up the departmental ladder over decades.
The neglect of statistics in general, and official statistics in particular, at most South African tertiary institutions; and competition from the private sector for qualified, skilled and experienced staff who are statistically and economically literate, and it is hardly surprising that Stats SA faces capacity constraints.
However, the consequences of these constraints have to be measured carefully against the quality and quantity of Stats SA's regular output.
Is the department, as some have suggested, "accident prone", or do the greater majority of statistical outputs appear regularly, on time, and without error?
A distinction must be made between error and a regular and planned cycle of revision and change.
Last week's release of manufacturing data contained an error, a miscalculation based on mistaken exclusion of data that had been collected.
The development of a new business register, resulting in better coverage of activity, and a consequent revision of previous data, was not an error. It involved improvement in data quality based on a number of years of planning and implementation.
Reweighting, rebasing and benchmarking of gross domestic product (GDP), which occurred during 2004, was part of the ordinary statistical cycle.
Revision of GDP estimates is a routine part of national accounting, while the international standard South Africa adheres to (the UN system of national accounts) requires national accounts estimates to be benchmarked frequently.
A Swedish report referred to in a recent paper by Len Cook, the national statistician and head of the British Office of National Statistics, makes mention of GDP revisions in 11 countries over a period of nearly 20 years - a powerful indication of the routine nature of statistical revision.
During 2004, Stats SA released about 230 separate statistical products, presenting information on hundreds of indices and sub-indices, and thousands of data items, often presented at different levels of geography.
Much of this data is derived from surveys, while some is the result of consolidation and analysis and, to a lesser extent, administrative records.
Output involves an average of one separate release each working day. Some of these statistical releases appear every month, 12 times a year (consumer and producer price indices, manufacturing data, and retail and wholesale trade figures, for example).
This necessitates conducting a survey every month, then capturing, editing and analysing that data, and publishing the results every month. Others are quarterly, such as GDP. Some releases appear only once a year.
The production load places tremendous strain on Stats SA's capacity, both in terms of the number of people available to undertake all elements of the complex statistical cycle, and their knowledge and experience.
Yet very few of the products released in 2004 contained errors. And those errors were usually at the level of a single data item or subindex, as in the well-known cases of November's error in manufacturing, and miscalculation of the rental component of the consumer price index.
Mistakes have certainly been made. These have been acknowledged and corrected.
They are unlikely to be the last ones identified. Capacity constraints, when an average of one data product, containing dozens of separate indices, subindices and data items, is being released each working day, create an omnipresent danger of error.
Transforming statistical production to meet the priorities and requirements of a new social order is sometimes like traversing an old minefield, left over from previous battles. Few know where the mines are laid. Sometimes, we do not even know what sort of mines they are, or what pressure will cause them to detonate.
However, if we do not take the risks necessary, and face the mistakes these might lead to, we will never clear the minefield, nor reach the other side.
Pali Lehohla is South Africa's statistician-general and head of Statistics SA. For more information on Stats SA and its statistical outputs, contact user services on (012) 310-8600.