A global survey says standards in reading, maths and science are falling.
Election Campaign Round-Up
A look at the campaign trail in Scotland: April 15th
Scottish Labour leader Jim Murphy insists his party can still turn the polls around, after one survey revealed almost a third of voters in Scotland remain undecided.
He said he is confident the party can win both north and south of the border, as he dismissed questions about deals with the SNP after the May 7 vote.
Opinion polls consistently show Labour trailing the SNP, with the nationalists on course to snare the majority of Scottish seats.
But a TNS poll published this week indicated 29% of voters are still undecided, rising to 39% in Glasgow - a key battleground for the main parties and a traditional Labour stronghold.
Speaking during a campaign event in the city, Mr Murphy suggested the fight for Scottish seats is yet to begin in earnest.
"The main (Scottish) parties haven't published their manifestos yet, and when that happens the campaign proper gets under way,'' he said.
"I am confident we will close the polls.''
The Conservatives and Liberal Democrats are dishonest and cannot be trusted to keep their promises or deliver more powers for Scotland, according to SNP leader Nicola Sturgeon.
Ms Sturgeon launched an attack on the coalition parties following the publication of a Tory manifesto yesterday which both the SNP and Labour deemed a betrayal of the Smith Commission on devolution, and a Lib Dem manifesto today which she said follows five years of austerity and "dishonesty''.
The Scottish First Minister today visited the offices of children's charity Barnardo's in Kirkcaldy.
She also attacked Tory Chancellor George Osborne, who is campaigning in Aberdeenshire today, and dismissed Labour shadow chancellor Ed Balls's insistence that he would reject any SNP demand that puts Scotland's interests over those of England.
Liberal Democrat leader Willie Rennie attacked the SNP's record on childcare as he argued 60,000 two-year-olds in Scotland would benefit under his party's plans.
Mr Rennie said youngsters in Scotland are "missing out'' because the Scottish Government has failed to match free childcare provision delivered in England by the UK coalition Government.
He visited a nursery in Edinburgh with Liberal Democrat candidate Mike Crockart as Nick Clegg launched the UK party's manifesto in London.
It includes a pledge to deliver at least 20 hours of free childcare a week for all parents with children aged two to four and all working parents from the end of paid parental leave at nine months to two years.
The provision of childcare is devolved to Scotland and Mr Rennie said the SNP administration had "failed to keep up'' with progress elsewhere in the UK.
Conservative plans to bar Scottish MPs from voting on income tax rates south of the border are "right and fair'', Chancellor George Osborne has insisted.
The senior Tory said the change, a consequence of plans to hand greater control over income tax to Scotland, would not damage the union but would instead create a "stronger Scotland within a stronger UK''.
The Conservative election manifesto, published yesterday, was quickly branded a "brutal betrayal'' of the cross-party Smith Commission proposals, which include transferring powers over income tax north of the border to Holyrood.
Scottish Labour leader Jim Murphy also claimed it would "fracture the UK tax system and consign Scots to second-class citizens in the House of Commons''.
In their manifesto, the Tories pledged to "extend the principle of English consent to financial matters such as how spending is distributed within England and to taxation - including an English rate of income tax - when the equivalent decisions have been devolved to Scotland''.
Engineering group Doosan Babcock is to cut almost 500 jobs across its UK sites.
The 82 year old was found with "catastrophic injuries" in her home in Leven in January.
Tributes have been paid to a Scottish tour guide who was stabbed to death in Lapland.
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