The following revision is taken from the dissertation of a Thai-speaking student of Occupational Health:

I have been making corrections of the type shown above for over thirty years: since we cannot write 'the same than', it is necessary to insert the preposition that is used with 'same'. The following citations (obtained from a concordance of 'or' + 'better/worse') support the correction:

1. Payne is doing as well as or better than any could.
2. In most other respects the flywheel performs as well as, or better than, lead-acid batteries ...
3. All men need to be proving themselves to themselves in terms of being as good as or better than the next fellow.
4. The ability of our models to discriminate among hospital groups was limited, but it is comparable to or better than other studies ...
5. Research by the University of Natal suggests that 2.8 million blacks now share household incomes equal to, or better than, those shared by 2.5 million whites.
6. ... for both borrowers and those in repayment 94 per cent found Student Loans Company's service to be as good as or better than the service provided by the banks.
7. In a VA system, for example, a school could be accredited if 75 per cent of pupils achieved as well as or better than the LEA average, although it would have to satisfy other requirements.

However, examination of my data produced also the following citations (most drawn from 'quality' newspapers such as The Times) which are constructed with 'mixed prepositions' in the same way as the student's 'mistake':

8. But, all in all, the economy is performing as well, or better, than it has in many a year.
9. More seriously, Hawaii had tropical locations as good or better than less accessible alternatives.
10. ... we would like to pass this estate and heritage to our heirs in as good or better condition than it is now..
11. As Charlie Scott said the other day, the morale at the other places is equal or better than before this happened.
12. Mr Salmon can invite tenders only from companies willing to run a train service almost as frequent or better than the existing one.
13. Moreover, the exchange rate you get at the airport will be as good, or better, than anything offered by your local bank or building society.
14. Sir, I will "feel good" when the state of repair of my grand-daughter's school is as good or better than that of the local betting shop. Yours faithfully,
15. ... compression techniques would let a 12-centimetre CD deliver over an hour of motion video as good or better than VHS tape, with stereo sound that is as good as CD.
16. ... the odds of making money in the stock market in the period around a Labour victory are as good or better than the odds in the period surrounding a Conservative win.

Should we, then, now accept this type of 'mixed preposition' expression as Standard English in correcting students' work? For the time being at any rate I shall continue to correct examples of 'mixed prepositions, on the grounds that of the four examples above drawn from academic and scientific texts only one showed the mixed preposition construction.