Friday, 9 January 2009

Another lesson in fiddling with numbers

If the numbers that you are using to make your case don't stack up, then you need to take some lessons from me in how to fiddle them. I spent 3 years studying accountancy, which is all about fiddling numbers, and then a few years working in the public sector, which is all about taking the fiddling to a new level. The way bureaucrats manipulate numbers, if properly researched, could lead to new theories about how the universe operates at a quantum level. It's like we exist in four dimensional space, but government numbers exist in five dimensional space.

I have spent the last few days looking at numbers that the NSW Education Department is publishing in an attempt to put a positive spin on their existance. Through the Daily Telegraph, this list of schools was published, showing falls in enrolments. Skip the list - most of it is boring.

  • Patrician Brothers' College, Fairfield: down 357
  • Saphire Coast Christian College, Bega: down 317
  • Emmaus Catholic College, Kemps Creek: down 291
  • SCEGGS Redlands, Cremorne: down 259
  • Australian International Academy, Condell Park: down 235
  • Terra Sancta College, Schofields: down 214
  • St Peter's Catholic College, Tuggerah: down 209
  • St Patrick's College, Campbelltown: down 191
  • Kindalin School, Penrith: down 181
  • St Gregorys Armenian School, Baulkham Hills: down 173
  • Norwest Christian School, Riverstone: down 164
  • Bethlehem College, Ashfield: down 159
  • St Joseph's Catholic College, Gosford East: down 145
  • Mary Immaculate Primary: Quakers Hill: down 144
  • Redeemer Baptist School, Castle Hill: 142
  • St Bernard's Primary, Batehaven: down 134
  • St Matthew's Primary, Windsor: down 128
  • Blue Mountains Grammar School, Wentworth Falls: down 126
  • Tyndale Christian School, Blacktown: down 124
  • St Jerome's Primary, Punchbowl: down 121
  • St Francis Xavier's Primary, Lurnea: down 120
  • Our Lady of the Rosary Primary, St Marys: down 117
  • All Saints Catholic Primary, Liverpool: down 120
  • Holy Spirit Primary, St Clair: down 122
  • Holy Cross College, Ryde: down 116
  • Pymble Ladies College, Pymble: down 114
  • Red Bend Catholic College, Forbes: down 113
  • Masada College High School, St Ives: down 111
  • St Euphemia College, Bankstown: down 107
  • St Michael's Primary, Nowra: down 104
  • De La Salle College, Ashfield: down 105
  • Carinya Christian School, Tamworth: down 102
I discovered the other day that the reason for the big fall in numbers by the number 1 school, Patrician Brothers' College, was that they closed their primary school over a period of years, thus shedding - wait for it - 357 pupils. Although the closure was obviously a decision made by the school some years ago, presumably to focus on the high school, this has been painted as a damning failure of the private system to attract fee paying students.

The Telegraph goes on to tell us that 439 (out of 917) private schools shed kids over the past 5 years. However, the full list is not published, so we don't know if many of those schools lost trivial numbers of kids - say 10 or less. For all we know, 31 might have shed over 100, and 408 might have lost 5 kids each - hardly the beginning of the end for the private system.

But we don't know the full picture at this point, because we have only been spoonfed a small fraction of the numbers. We have been fed those numbers that paint the private system in the worst possible light.

We also haven't been given any numbers for the remaining 478 schools that remained static, or grew their numbers. For all we know, some private schools might have added 300 pupils - but we aren't allowed to know that. Surely they must have added some, because the net gain for all private schools between 2002 and 2007 was in fact around 20,500.

So some schools shed pupils, but the sector as a whole gained enrolments. Something doesn't add up, meaning the Telegraph (and some stooges at the Dept of Education) are hiding a whole swathe of numbers from us.

But I have only just begun.

The Department, in its wisdom, put out a press release entitled "Schools with significant enrolment increases 2003-2008". It only covers state schools of course.

The press release opens with the words:

Over 738,000 students are enrolled in more than 2200 NSW public schools. In many areas across the State, public schools are experiencing significant growth in enrolments.

That may be true - in many areas, public schools are experiencing significant growth. But in 2002, public school enrolments stood at 753,700 - over 25,000 higher than today. If some schools are experiencing significant growth, others must be experiencing a catastrophic haemorhaging of pupils. Otherwise, how could the state system lose 25,000 overall?

But the Department doesn't mention any of that. No, that would be like talking to the Germans, and mentioning the War.

The Department is kind enough to tell us though that:

Significant enrolment growth is said to have taken place when enrolments have increased by 20% or more and where the actual increase in the number of students is greater than 20.

The press release doesn't make it clear, but they measure enrolments at three different phases - kindergarten, year 8 and year 11.

Of the schools showing growth, 63 are kindergartens. Given the baby bonus started 4 or 5 years ago, it would not surprise me to find that we are about to see a wave of baby bonus boomers hitting kindergarten. You could put part of this down to the Costello impact on demographics.

There is also the failure of ABC Learning childcare centres to think about. Have parents decided to move their kids out of childcare a bit earlier and into kindergarten? Who knows. It's possible, but the Education Department is not into investigating causes - it's just into shouting triumphantly about some numbers that make it look good, even if it had no impact whatsoever on producing those good numbers.

Only 43 schools showed growth at year 8, and I notice that one is Braidwood.

Braidwood is a small town on the road between Canberra and the coast. It's a lovely place, full of antique stores and cafes. Canberrans stop there for a coffee and a French clock on the way to Jervis Bay.

I went to the Private Schools Directory and did a search for private schools in and around Braidwood. Result - zero.

So it's not like the Braidwood state school has gained lots of kids from a failing private school nearby - because the nearest one is over 100km up the road in Canberra.

In the postcode of Braidwood, there were 2,740 people in 2001. The 2006 census listed 3,037 - growth of nearly 300 people. Braidwood is a classic "tree change" town. Those in the 5 to 19 age group make up 17% of the population.

17% of 2,740 people is 466 - that is the potential school population in 2001.

17% of 3,037 is 516 - the potential school population in 2006.

Gee - an increase of 50 students, just like that from more people moving to a town of 3,000 people.

The Department says that Braidwood experienced growth of over 60% in year 7 enrolments between 2003 and 2008. Should we be impressed? I don't know. They don't make any annual reports available on the internet.

Let's make some assumptions and play with the numbers.

We know that in country towns, enrolments at schools are "lumpy". If lots of people had kids in one year, you might have 50 in grade 6 and 20 in year 7. You can't shuffle kids between the nearest schools to smoothe the numbers out for each year.

But let's assume that of the 466 kids in Braidwood in 2001, all went to school. That gives an average of 36 per year (assuming kindergarten through year 12).

In 2006, due to population growth (all those bloody tree changers), the average per class is 40.

Why shucks, I have just conjured growth of 11% out of thin air!

But what if the demographics are lumpy? What if in 2001, there were only 30 kids enrolling in year 7. But come 2006, due to tree changers moving in, and the lumpy demographic profile, we now have 48 enrolments. Shucks again! Growth of 60%!

This allows the Department to claim a victory for state education, as a massive 60% growth must mean that parents are flocking to the state system.

Yep. 250 adults move to Braidwood, bringing 50 kids with them. They can't go to a local private school, because there isn't one. The town is not big enough to support a state school and a private school - not with only 500 kids. Then we factor in some lumpy demographics, and we can claim 60% growth.

I, for one, am less than impressed.

We normally refer to that as "gilding the lily".

If you read the press release carefully, quite a few of the schools showing high growth are in the sticks. Check out these names:

  • Alstonville - somewhere on the north coast near Ballina. Population of 10,660.
  • Canobolas Rural
  • Gilgrandra, population 4524.
  • Inverell
  • Molong, population 2780

When it gets to year 11, the number of schools showing growth drops off to 22. Those include:

  • Boggabilla - pop 1250
  • Dunedoo - pop 1970
  • Coomealla, which doesn't even appear on the map. It appears to be near Gilgandra, pop 4524.
Trumpeting great growth at schools in these towns is really gilding the lily, especially when a lot of them probably don't have a private school nearby.

Apart from demographic change, what could cause growth in state school enrolments in small country towns?

Hmmm. How about a drought? Did any of these kids go to boarding school in Sydney previously? Are their parents now so broke, they have to educate them closer to home, and more cheaply?

And what could cause enrolments in year 11 to increase?

A threatened recession perhaps? Might not kids that were planning on leaving school in year 10 to become an apprentice plumber now be finding that the apprenticeships have gone as the building industry has collapsed, so they are staying on at school for two more years to ride out the recession?

I can think of many reasons why these changes might be happening.

But let me go back to the table that I put in at the start of this blog. I'll just lift a few entries:

  • Patrician Brothers' College, Fairfield: down 357
  • Saphire Coast Christian College, Bega: down 317
  • Emmaus Catholic College, Kemps Creek: down 291
  • SCEGGS Redlands, Cremorne: down 259
  • St Gregorys Armenian School, Baulkham Hills: down 173
Note that for private schools, the raw numbers are listed. But the total number of enrolments is not listed.

When it comes to state schools though, we get no raw numbers. We get percentages. In fact, we don't even get percentages - we are told "this many schools increased enrolments between 20% and 40%". For all we know, they all might have increased enrolments by 21%, but who is going to know? It sounds much better to give a range, and so long as no one sees the underlying numbers, no one will be the wiser.

That last bit was the crux of my lesson. Present numbers on the same subject in two different formats to confuse the issue. Present one as raw numbers, and the other as percentage bands.

We are also told that SCEGGS lost 259 students over 5 years. I thought I'd have a look at their annual report for 2007. It shows 1498 students being enrolled. If they lost 249, it means they must have started with 1757. A drop of 259 students is a drop of 14%.

A fluctuation like that can be explained by the market for foreign students:

Both the apparent and actual retention rates are fluctuating. This is largely due to the semi international nature of the student cohort. 17% of the (SCEGGS) school population is expatriate, therefore there is an ebb and flow of students over all age groups annually.

In 2007, Enquiries recorded a 9% increase over the previous year and applications increased by 20%. Student numbers achieved a net increase of 3% throughout the year.

It's possible that the outflow of students from SCEGGS might have been largely caused by Asian parents deciding to educate their kids closer to home. A strong Australian dollar would not have helped. The drop of 259 students might not have added a single child to the state school system. With the fall in the value of the dollar, making us a cheaper education destination, they may pile the numbers back on in no time.

That's my rant for the day over. I've had enough of looking at numbers.

All I can say is that whenever a government department releases any statistics that make it look good, be very suspicious. Be even more suspicious of people who are in love with the state system proclaiming the death of the private system.

The state school system has its place, but I don't believe it is the role of education bureaucrats to bash the private system in order to build their empires.


Anonymous said...

I'm out of the loop when it comes to NSW politics but know enough to know it's stuffed. And this all seems like the Education Department (and by proxy, the NSW Labor government) is trying in vain to make the shit sandwich they've served up to the public taste good.

Anonymous said...

Many people know what you have stated but don't waste time telling others.
This is how society spirals downwards by politicians not "informing".
Overall more go to Private schools.
Overall the Government is happy "less expense" for them.
You mentioned St. Gregory's School, from 2003 the population went down because they were told to reduce numbers or close the school as they have more children than allowed.

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