Sir Stephen House, Chief Constable of Police Scotland, told officers that "roughly" 25% of searches should be positive - up from the publicly-quoted figure of 15%.
However, a police source queried both numbers on the grounds that some officers are allegedly inventing searches to inflate the statistics.
"Stop and search" is intended to detect drugs, knives, alcohol or stolen goods, and is a policy strongly associated with House during his spell as Strathclyde chief.
Searches can either be positive, which means that an illegal item was found, or negative: shorthand for drawing a blank.
Recorded levels of violent crime fell on House's watch at Strathclyde, a reduction partly put down to more searches. In 2012-13 alone, more than 600,000 searches were conducted by Strathclyde officers, which one report claimed was four times higher than the "stop and frisk" rate in New York City.
After House took over at Police Scotland last year, his strategy to combat violent crime was rolled out.
According to the Scottish Police Authority, which holds the new force to account, the key performance indicator is that "at least" 15% of all stop and searches should "recover weapons, drugs and other unlawful items".
However, a presentation from the chief constable on stop and search, which was distributed internally in January, asks for a higher proportion of positive results.
His briefing confirmed there were no targets for the number of searches for individual officers, but it noted: "All [that] officers should be concerned with is stopping the right people in the right place at the right time. If you are, you should be finding something - drugs, weapons or alcohol - roughly one in every four stops."
House also gave examples of what should not be recorded as stop-searches, including: a prisoner in a custody suite; a "pat-down" at a turnstyle; and a vehicle search that has not resulted in a search of the occupant.
The Sunday Herald recently reported claims by former officers of some searches being made up due to pressure to keep the numbers up.
The Scottish LibDem's justice spokesperson, Alison McInnes, said: "We are worried that the use of this tactic, so commonly used in Strathclyde, is now increasing across Scotland ... Given the fact that this tactic is used to both tackle and deter crime, the proportion and value of such targets should be justified through evidence and open to scrutiny."
Police Scotland's Deputy Chief Constable Rose Fitzpatrick said: "The use of stop and search ... is an effective and legal tactic that helps us support community policing priorities.
"In the first nine months of Police Scotland, the number of positive searches has increased, removing more drugs and weapons from our streets, while the number of stop and searches across the country has reduced."