Valence refers to a party's image in the eyes of voters.
Economic competence; in 2010, Labour were defeated due to their handling of the 2008 Financial Crisis; in 2016, new Chancellor Philip Hammond pledged to be 'pragmatic'.
Party unity; John Major inherited a disunited party over Europe.
Leadership; voters desire strong leaders - Major seen as weak, Blair said 'I lead my Party, he follows his'.