Tactical voting did not play a huge part in the outcome of last year's Holyrood election, analysis has shown.
The research was carried out by the Electoral Reform Society (ERS).
The SNP won 63 seats in last May's poll, down from 69 in the 2011 ballot and two seats short of an overall majority.
The "main reason" why the SNP lost its majority was because the party failed to win a number of key constituency contests, the report said.
Author John Curtice, who is professor of politics at the University of Strathclyde, said there was "little consistent evidence" the SNP suffered because unionist voters "ganged up" by voting for whichever of the unionist parties appeared best placed to defeat the nationalists.
Speaking to BBC Radio Scotland's Good Morning Scotland programme, he added: "The crucial reason why the SNP failed in the end to win the overall majority was because of results such as that of Ruth Davidson.
"There were a number of constituencies, Fife North East, Dumbarton, Aberdeenshire West and a couple in Edinburgh which the SNP should have won given that increase in the share of the vote and the fallback in Labour support and the Lib Dems not going anywhere - but they failed to do so.
"It was the failure to win some of these crucial constituency contests that denied the SNP the overall majority."
Prof Curtice went on to say that the party was not "compensated for in the allocation of list seats because it had already won its proportionate share of seats in the constituency contests".
The research also found that campaign warnings to nationalist supporters that using their second vote for the Greens would bolster unionist parties were also unfounded.