On Election Day, Mitt Romney had a victory speech prepared -- but not a concession. He believed he would win. His confidence was based in part on internal polls showing an electorate that favored Republicans. Many Republican Senate candidates also got false optimism from their numbers. 

In a memo, the firm of Romney pollster Neil Newhouse, Public Opinion Strategies, explains its mistakes and suggests how to fix them going forward.

As a part of the Republican polling community, our prescription includes doing at least one-third of the interviews with cell phone respondents going forward, adjusting as required, ensuring that we include enough younger voters in our sampling, and (in many cases) polling until the final weekend of the campaign. This is going to cost campaigns and organizations more money on polling, but it is necessary to have a more accurate representation of the electorate.

Pollster Glen Bolger of the same firm elaborates in a followup, saying he missed Obama's growing share of the Latino and Asian vote, underestimated the youth vote and was surprised by an electorate that gave Democrats a six-point party ID advantage.