Responding to the Programme for International Student Assessment results, Aled Roberts, Welsh Liberal Democrat Shadow Education Minister, said:
"This is not a good day for education in Wales. Following the dismal PISA results in 2010 and the subsequent strategies and action plans laid out by the Welsh Labour government to address the poor performance, the people of Wales were rightly expecting to see an improvement in Wales' international standing. Disappointingly, this is clearly not the case. This is the culmination of over a decade of Labour being in control of our failing education system.
"There is a risk that for politicians, particularly those responsible, a panic switch is flicked on when their programmes and strategies seem to have failed. What the Welsh education system doesn't need now is a panicked Welsh Labour government making further knee jerk reactions. The Welsh Labour government needs to be honest about the PISA results for 2015. Instead of making grandiose statements about setting wildly unrealistic targets, the Welsh Labour government should concentrate on making sure that Wales travels up the league tables, instead of slipping further down.
"From one week to another, the performance of the Welsh education system hits the media headlines and portrays Wales in a very negative way. These rankings are seen by the rest of the world and the Welsh Labour government cannot spin their way out of this mess. Wales can spend millions of pounds on marketing abroad to attract inward investment but that spending will prove futile when international corporations look at these world comparisons.
"The Welsh Labour government must realise how their failure is having an impact on Wales as a country. This is not good for the morale of our teachers. It is not good for the standing of Wales as a country to invest in and, most importantly, it is not good for the educational development and the future prospects of Welsh pupils.
"The Education Minister's statement on these results clearly undermines the position the First Minister has been taking for the past two years. He has consistently said that he expects to see improvement is Wales' scores. He was either badly briefed or seriously in denial. Following these disappointing results, it is time the First Minister showed some leadership and took control of this seriously underperforming aspect of his government."