Wales is in danger of missing out economically unless it improves its performance in global education tests, a former government advisor has said.
Prof David Reynolds warned ministers would miss their targets for the Pisa tests unless teacher training improved.
Industrialists made investment decisions based on this “most important test”, he told BBC Wales.
The Welsh Government said initiatives to raise standards should result in an improvement at the next tests in 2018.
The Pisa tests – a major study of educational performance – are taken by 15-year-olds in 72 countries every three years.
Students in Wales were the lowest of the UK nations in science, reading and maths in the 2015 tests, scoring 478 in maths, 477 in reading and 485 in science.
Speaking to Sunday Politics Wales, the Swansea University head of education said: “In a globalised world Pisa is the most important test that there is.
“If you look back at 2010 when Shanghai, China, suddenly came from nowhere to be top, foreign investment in China went up.
“If industrialists are looking at Pisa – and they are – the answer is to get those scores up to get industry in or we risk becoming just a kind of theme park with no industry.”
In 2014 the Welsh Government set itself a target of reaching a score of 500 in the three subjects by 2021.
After Education Secretary Kirsty Williams recently distanced herself from that goal, First Minister Carwyn Jones reiterated his government’s commitment to it.
Asked if the goal could be reached, Prof Reynolds said: “If teacher training improves, if we get the knowledge base out there and if we make our teachers master craftsmen and women of teaching which many countries have done, then we could be very, very close to those targets.
“But I fear at the moment we’re not doing it so it ain’t gonna happen.”
Owen Hathway, Wales policy officer for the National Union of Teachers, said confusion over the government’s policy left the profession asking “whose target are we aiming for?”
“Should we be aiming for targets at all and, if so, what merits are we being judged on?
“Are we being judged on the performance as set out by the education cabinet secretary or by the Welsh Government itself?
“If we don’t have clarity on that, then it becomes even more meaningless really to put weight on Pisa results.”
A Welsh Government spokesman said the education secretary’s focus “remains on the next set of Pisa tests in 2018 where we expect to see improvement”.
“Pisa allows us to judge ourselves against the world – everybody in our system must understand this,” he said.
“It is a check and review against our development and will remain so.”
The spokesman pointed to measures aimed at boosting the quality of teaching, from initial training and career development to a new National Academy for Educational Leadership.
“These actions reflect our shared ambitions and pride for the profession,” he said.