Trying to submit TMA01 for M253, and I’m being greeted by this wonderful caption. Again. Seems the OU’s new web platform is best described as “shaky”.

Due to a problem, we’re currently unable to display your course content.
Our technical staff have already have been notified, and will be fixing it as soon as possible.
We apologise for the inconvenience.

Grrr. And Aaargh. Apparently it’s not just the M253 website that’s affected, so that makes me feel a little better (TMA extensions all round, anyone?), but still… Time to thwack OU tech support with a clue-by-four…

In the end, I solved the issue myself and the ECA is now away – but the prospect of being unable to complete an ECA, and therefore failing the course, through no fault of my own has left a bit of a bad taste in the mouth. Here’s hoping it doesn’t happen again.

T224′s TMAs are weighted as follows:

TMA01     15%
TMA02     30%
TMA03     30%
TMA04     25%

My highest TMA score was on TMA04; the lowest, on TMA03. On TMA01 and TMA02 I had the same score – although the different weighting means they contribute different amounts to my Overall Continuous Assessment Score (OCAS).

So. The substitution score is the weighted average of your POCAS & exam score; it cannot be used to substitute any higher TMA score; and where there’s a choice of eligible TMAs, it must substitute the one that makes the lowest contribution to the OCAS. Fairly clear rules – there’s a paper worksheet to help you work it all out yourself, but both Marx and the Assessment Calculator on StudentHome will both work it out for you.

Here’s where the fun starts. In my case, once you get an exam score of 85% or over (a requirement for a Distinction, which is what I’m interested in), there are 3 distinct score ranges that produce different results:

85%-89%
An exam result in this range gives a substitution score that can only be used to replace my lowest TMA score – which conveniently was on one of the highest-weighted TMAs. End result: an OCAS over 85% and a guaranteed distinction.

90%-91%
At 90%, with a slightly higher substitution score, another TMA score comes into the substitution range – and it’s TMA01, the one with the lowest weighting (same original score as for TMA02, but because it contributes less to the POCAS because of its lower weighting, it’s the one that gets substituted) – and because of that, the OCAS is left below the 85% threshold, leaving me with a Pass 2.

92%-100%
In this range, even when applied against the lowest-weighted TMA, the substitution score is enough to guarantee an OCAS over 85%, and puts the overall result into the Distinction range again.

I can follow how the rules work easily enough, and on courses where the TMAs are equally-weighted there wouldn’t be an issue. As I’ve shown, though, different weightings can throw up some frankly silly inconsistencies. Hopefully, this is one of those circumstances where the Examination and Assessment Board can exercise a little discretion – otherwise I’ll be one very unhappy bunny should I score 90% on October’s exam…

I’m currently waiting on my mark from TMA04, but depending what I get there, the substitution system is throwing up some unusual vagaries that seem to flow from the different weightings on T224′s assignments (TMA01 15%, TMA02 30%, TMA03 30%, TMA04 25%) that could leave me needing a very specific mark on the exam (85%) to guarantee a distinction – any lower and the OES is below the threshold, any higher and the substitution score switches to a TMA with a different weighting and leaves me short on the OCAS. It’s all theoretical at the moment, but I’ll be looking into this a bit more once I have my TMA04 score, as I’d consider the possibility of getting a Distinction for scoring 85% in the exam, but a Pass 2 for scoring 86%, to be something of a glitch in the system…