Archive for the 'Statistics' Category

Small schools are not more expensive

September 28, 2006

Small schools are not more expensive. This may come as a surprise to anyone who has seen the Government’s misleading cost per student figures. All schools have some fixed costs regardless of how many students attend the school, and then the costs increase linearly with the number of students.

This can be seen in the following graph, which plots total cost of ACT Primary Schools versus size (student enrolment):

Read the rest of this entry »

Tuggeranong a shambles? Belconnen a farce

August 9, 2006

If the tuggeranong figures are a shambles then the numbers for North West Belconnen are a farce. The total number of primary school students in their North West Belconnen region in 2010 is projected to be 2515. This is for the current situation. Under the Towards 2020 proposal* it is 3089, a difference of 574. This is largely due to the students from Holt and Higgins being double counted. They have been redistributed to surrounding schools but the new West Belconnen school (P-6 initially) has also been included.

How to fix it? Let’s start with treating Belconnen as one region. Splitting Belconnen up was only ever a political ploy to make the school closures more palatable.

Here are the projected 2010 enrolments for Belconnen as given in the Towards 2020 proposal:

.          School    Status quo Proposal Difference
1       Charnwood PS        175      220         45
2           Evatt PS        140      430        290
3          Florey PS        345      480        135
4           Flynn PS        150        0       -150
5          Fraser PS        350      374         24
6         Higgins PS        190        0       -190
7            Holt PS        150        0       -150
8          Latham PS        195      310        115
9       Macgregor PS        325      350         25
10 Miles Franklin PS        370      425         55
11   Mount Rogers PS        125        0       -125
12    West Belconnen          0      500        500
13         Aranda PS        350      350          0
14           Cook PS        135        0       -135
15       Giralang PS        145        0       -145
16         Hawker PS        210      210          0
17         Kaleen PS        395      450         55
18      Macquarie PS        220      275         55
19    Maribyrnong PS        185      350        165
20 Southern Cross PS        175      110        -65
21     Weetangera PS        250      330         80

It is not clear how to remedy the numbers for Belconnen. If we assume all of Higgins and Holt go to the new West Belconnen School, plus 65 from Southern Cross, then we get 405 for West Belconnen. In the ballpark for the Towards 2020 number of 500. That leaves 125 from Mt Rogers and 150 from Flynn to be redistributed.

The Towards 2020 plan redistributes pupil numbers where they will conveniently fit, not where they might actually want to go. Just to get some idea of the situation in 2010 we will make some arbitrary assumptions about where to place the displaced students.
Starting with Flynn, their closest schools would be Charnwood, Fraser and Latham. Charnwood is not a destination of choice. To get to Latham they would have to go under Ginninderra Drive. Fraser is full already. Regardless we’ll split the Flynn kids three ways, 50 each to Charnwood, Fraser and Latham.

The obvious choices for kids who currently attend Mt Rogers would be Miles Franklin and Evatt. Miles Franklin is fairly full, so we’ll top it up with 55 kids and the other 70 we will place in Evatt.

Kaleen and Maribyrnong only have to accommodate 145 from Giralang, but they are listed as changing by 55 and 165 respectively. Perhaps someone thought they were redistributing 220 students? In any case if we assign 70 to Kaleen and 75 to Maribyrnong this is the result:

.          School    Status quo Proposal Difference
1       Charnwood PS        175      225         50
2           Evatt PS        140      210         70
3          Florey PS        345      345          0
4           Flynn PS        150        0       -150
5          Fraser PS        350      400         50
6         Higgins PS        190        0       -190
7            Holt PS        150        0       -150
8          Latham PS        195      245         50
9       Macgregor PS        325      325          0
10 Miles Franklin PS        370      425         55
11   Mount Rogers PS        125        0       -125
12    West Belconnen          0      405        405
13         Aranda PS        350      350          0
14           Cook PS        135        0       -135
15       Giralang PS        145        0       -145
16         Hawker PS        210      210          0
17         Kaleen PS        395      465         70
18      Macquarie PS        220      275         55
19    Maribyrnong PS        185      260         75
20 Southern Cross PS        175      110        -65
21     Weetangera PS        250      330         80

Which adds up to 4580 students in total for the status quo projections and the Towards 2020 proposal.

Under my scenario Evatt goes from a projected enrolment of 430 down to 210! The Department needs to release some amended figures. How can parents even hope to plan where their kids will go when the figures are so wrong?

* I chose option 2 as it is simpler to add up the numbers, otherwise I would have to make messy assumptions about how many of the year 5-8 students in the Melba middle school ended were previously in Charnwood.

Update: I think I have worked out the South East Belconnen inconsistency. Of the Cook kids 55 go to Macquarie and 80 to Weetangera (and none to Aranda … hmmm). There were 65 kids left to place from Southern Cross (going from P-6 to P-3), so they have plonked them in … wait for it .. Kaleen! Huh? I am pretty sure they have then double counted these kids and assigned them to the new P-10 super school at West Belconnen.

Demountables fear for pupils

July 28, 2006

That demountable buildings will be required to cater for students displaced by school closures is a disgrace (“Demountables fear for pupils”, July 28, p4). It shows the poor level of planning in the Government’s proposals.

From the Government’s projections, by 2010 one third of primary schools will be above 90% capacity with little or no spare room. These are 2010 figures. By the Governments own reckoning even more students need to be accomodated in 2007, 2008 and 2009. By design, then, there will be overcrowding in one third of Canberra’s primary schools.

The Government’s own population projections assume a steadily decreasing fertility rate and yet we know that fertility has increased for the last four years in the ACT. Under the Towards 2020 proposal, displaced students have been “assigned” to other schools to conveniently round out capacity figures with no thought to where parents will actually want to send their children.

We have a recipe for overcrowding in our public primary schools. High irony, except for the affected kids and their parents, who, it should be noted, are eligible to vote.

Ranking schools by Salary and Management Costs

July 17, 2006

When the Stanhope Government first released their Towards 2020 plan they used misleading statistics to paint small schools in as bad a light as possible. Their per-pupil costs included costs like depreciation. When fixed costs such as depreciation are calculated the cost per pupil for smaller schools will always look worse than larger ones.

Later we found out that their projected savings were only calculated on some salary savings and schools based management (SBM) costs. I’ll have something to say about the SBM later, but if we take them at their word and just rank primary schools by salary and schools based management costs we get the following list (* = closing school):

Read the rest of this entry »

Projected enrolment for Turner incorrect

July 9, 2006

The projected enrolment at 2010 for Turner Primary under the Towards 2020 proposal is listed as the capacity (350), rather than unchanged from the 2010 status quo projections (275).

Tuggeranong Figures a Shambles

July 7, 2006

The projected enrolments in Tuggeranong under the Towards 2020 plan do not match those quoted for the status quo.There are five hundred more students under the Towards 2020 proposal.

Two glaring errors are obvious:

Read the rest of this entry »