The social work system has responsibility for more than 15,000 children in Scotland.
In more than half of these cases, children remained with their family but under the supervision of a social work department.
One of the recommendations of the inquiry set up after the murder of eight-year-old Victoria Climbie in London in 2000, was that social workers should supervise no more than 14 such cases.
Two young people who recently left a care home talks about their experiences
Scottish Labour leader Iain Gray said it may be better to care for more children in residential care rather than leaving them under inadequate supervision in the community.
He said: "We have to challenge the presumption that the best place for a child is always with their family.
"The conventional view is that children should only be taken away in the most extreme of circumstances. This is wrong. We need to change the balance between leaving these children with their family and keeping them safe.
"The time has come to challenge the orthodoxy and be quicker to remove and protect."
The Scottish Government said the percentage of children under local authority care had risen steadily in recent years which showed that social work departments were getting support to those young people who needed it.
Angus - 22
Clackmannanshire - 20-25
Dundee City - 15
East Dunbartonshire - 21
Fife - 13
Glasgow - 7
North Ayrshire - 19
North Lanarkshire - 24.5
Renfrewshire - 18.4
Shetland - 34.85
West Lothian - 15-20
The government also said recent figures had shown that the number of social workers in children's services was at its highest since records began - up by more than 500 since 2003 - which it said demonstrated its commitment.
"The choice of taking a child into care or leaving them in a family is one of the hardest that society is faced with," a government spokesman said.
"Getting the balance right relies on placing the best interests of the child first and ensuring that the decision to take any child into care is made by professionals at a local level with detailed knowledge of the situation."
Ronnie Stevenson, from Unison, said: "The figures themselves are bad, but they only point to the real problem - if there are too few social workers and too many cases, the crucial element of time spent on any one child is squeezed - especially if this is exacerbated by high levels of paper work.
"This situation is no good for social workers and it's no good for their clients who desperately need help."
The investigation, Home Is Where The Hurt Is, will be shown on BBC1 Scotland at 1035 BST on Tuesday, 14 July.
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