Bell Curve - To remove or not to remove?

[S6169]

AWSP:

iii) what is the thought process in the design of the T-score
I re-emphasize that this is just a discussion of interest.
There are other issues that kiasuparents should examine carefully:

a) are we on the right track with the type of testing in Science and Maths?
b) are we making a big detour doing models and heuristics in Maths which all the kids ditch in secondary school?

c) can pure rhetoric that all schools are the same solve the stress and competition issue without bringing the secondary schools more or less in line in terms of quality and facilities?

d) should we adjust the requirements in mother tongue so that it is not so \"punishing\" while we want to encourage or promote the learning.

T-score is but one small part of the broadbased issues that we are facing.
I am not one to accept all \"truths\" without examining the \"truths\" first.

:goodpost:

[ruohoo97]

AWSP:

the whole exercise of t-score is just for the single purpose of sec school allocation by merit and nothing else. the guy ranked higher will choose his sec school first. that's it

t-score is not a measure of cleverness or ability (in a narrow sense) but it takes into account carelessness on the actual exam day

and it is totally meaningless to compare t-scores across different years / cohort...as there is zero meaning to rank one guy from this year against another guy from another year...

if everyone is given unlimited amount of time, everyone will score full marks and have the same score

the guy who \"invented\" the t-score formula is now the principal of NUSH

well, for those people who demand for \"transparency\" aren't they insinuating there is cover up ? after all the t-score formula is not a state secret, and the PSLE markers are their teachers
You missed my point. While I agree with you on that we may need a granular formula which is because of the competition for places into the IP school., my hypothesis is
a) the t-score is designed SOLELY for data fitting into nice channel of 0-100 ( or even less) and NOTHING ELSE.
b) we have over speculated on that a difficult paper equate to low SD etc. I can easily design a paper where everyone score 0-10 marks for a difficult paper(low SD) or everyone score 90-100 for an easy paper (low SD again). Anything in between is unpredictable and pure speculation. AND it is not in the design.
There is no need to name the architect fof T-score although I know who he is as you have known.
I am re-engineering the thought process in the design as a point of interest and not because I am crying foul.
c)By virtue of points a and b, there are unintended effects which will be interesting to study as well.

the t-score formula is NOT just for competition for IP places.

it is used for ranking for the whole cohort to determine who has the right to choose his school before the next guy, including the guy with t-score of 43

why are people so fixated with IP or the top 10%? the root cause is really the sour grapes attitude mixed with kiasu mentality

why can't people recognise and accept that normal distribution of talent and examination ability exist in the population ? what is wrong by accepting such truth ?

do you guys seriously expect everyone to be able to score the same top marks ? then the questions will be set even more difficult to differentiate the differing ability of every pupil...want more stress ?

a) I dont think the guys on this thread are sour grapes or fixated over the IP schools placing. For me, PSLE is over and this PSLE has no bearing on me or my kids as the youngest have DSAed into an IP school and is not taking part in the S1 posting. (her Tscore is sufficient to qualify her into the school any way)
b) the point of interest is that I am trying to get people to open their eyes and not take too many things for granted like
i) normal distribution - even in finance and economics, researchers are shifting out of normal distribution into fat tailed distributions and skewed distribution (power law distribution). Can we be so sure?
ii) are there some unintentional effects in the design of the T-score. Does it cause distortion?
iii) what is the thought process in the design of the T-score
I re-emphasize that this is just a discussion of interest.
There are other issues that kiasuparents should examine carefully:
a) are we on the right track with the type of testing in Science and Maths?
b) are we making a big detour doing models and heuristics in Maths which all the kids ditch in secondary school?
c) can pure rhetoric that all schools are the same solve the stress and competition issue without bringing the secondary schools more or less in line in terms of quality and facilities?
d) should we adjust the requirements in mother tongue so that it is not so \"punishing\" while we want to encourage or promote the learning.
T-score is but one small part of the broadbased issues that we are facing.
I am not one to accept all \"truths\" without examining the \"truths\" first.[/quote]

Thanks AWSP, thank you for detailed insight on Tscore, very enlightening indeen. The only thing, although sometimes distorted, Tscore is so far the best placement measurement to serve this ranking purpose. Unless MOE wants to another holistic approach for students to select secondary schools, visa verse, the bell curve will stay for a while.

[AWSP]

ruohoo97:

Thanks AWSP, thank you for detailed insight on Tscore, very enlightening indeen. The only thing, although sometimes distorted, Tscore is so far the best placement measurement to serve this ranking purpose. Unless MOE wants to another holistic approach for students to select secondary schools, visa verse, the bell curve will stay for a while.

I think the first step to solving the issue is the recognise the distortion effect it creates. I would say that this contributes to a lot of unnecessary uncertainty and we cannot discount the magnification effect and the distortion in the weighting between the subjects. As atutor2001's exercise also pointed out and as I highlighted in the switching of the sign for those students with a subject that is particularly weak, landing on the wrong side of the mean really penalise you if you are not with the rest of the crowd in a skewed distribution.
Most importantly, the whole thought process of the Tscore appears to be all about fitting the score into 0-75 ( I think the designers did a very conservative fitting and use the factor 10/(standard deviation). Why not just take the percentile rankings for each subject and add together? There will be no distortion and true equal weighting while maintaining the whole objective of ranking. But the formulation will not look so \"sexy\" and appears too simple. I reserve my critical comments on the designers of Tscore for making such a \"marketing\" move.

The simple method above may lose a very tiny bit of granularity but we have to be aware that the granularity from the present Tscore comes from distortion in weighting. However as with all detailed ranking, the method I just proposed may be too clinical and not palatable to most.

My own \"socialist\" leaning is to have grades with percentile ranking for the award of the grades and point system for the grades. However this will definitely not be granular enough for sorting into schools. I maintain my view that rhetoric aside, MOE has to bring the schools more or less in line in terms of standard. Or it has to increase the supply of places at the IP schools both at PSLE and at 0 levels. Only then parents and students have the \"true option\" of selecting the school to match their pace. The current allocation of places for O levels entrants into the IP schools is ridiculous because of the IP programs. Thats why everyone is \"stampeding\" at PSLE.

I will not claim moral highground and say parents are too fixated with IP school because we are all guilty of putting our kids into the best schools that they can get into. And we are all aware that the chances narrow sharply after PSLE which is why PSLE is a high staked exams.

[AWSP]

1girl1boy:

:goodpost:

But I think your effort is falling on deaf ears.
I suggest that we leave this forum since both you and I are done with PSLE.
Don't waste your effort.

Congrats for finishing PSLE as well. Couldn't resist the posting while waiting for the US markets to open.

[ruohoo97]

Dear AWSP; again appreciate your insight, Please keep posting and also make your point across to MOE, I believe you have a valid point! Since MOE is looking at reducing the stress level of PSLE, I am sure they will welcome any constructive suggestions.


On the side note, PSLE is one-and-all exam for majority students, except DSA CO /WL students, that is also a cruel reality to some students like my dd’s classmates. A few of them were constantly top of school, but their t score for PSLE were 25+, very unlikely to go to their dream schools. The luck factor during exam plays a part. So if MOE allows 40% P4-P6 academic performance and 60% PSLE score, that will greatly reduce the stress for one exam.

[PreU_SGstudent]

Hi everyone! :scared:


I have been PSLE/ O levels/ A levels. To me, bell curve is essential to get into the place in higher institution. It is like a distinction of merit and your hardwork. My personal take is that, bell curve is used to differentiate A and B student and also C and D student. 

However, bell curve hits hard on A level students especially. In A levels, we are competing with the almightly. So therefore, it will be the survival of the fittest. 

Bell Curve on the other hand, helps in stronger students than the weakens which will hinder the gap even more. 

:hi5:

[Skyed]

PreU_SGstudent:

Hi everyone! :scared:


I have been PSLE/ O levels/ A levels. To me, bell curve is essential to get into the place in higher institution. It is like a distinction of merit and your hardwork. My personal take is that, bell curve is used to differentiate A and B student and also C and D student. 

However, bell curve hits hard on A level students especially. In A levels, we are competing with the almightly. So therefore, it will be the survival of the fittest. 

Bell Curve on the other hand, helps in stronger students than the weakens which will hinder the gap even more. 

:hi5:

Yeah without the bell curve the whole of Singapore would score A1 for emath if the A1 was really at 75. .__. The bell curve pushes the A1 up to 90+ because of how easy the papers are.

[Jovialcho]

The bell curve for national exams is here to stay and relevant.