The Positive Affect Negative Affect Schedule (PANAS) is, according to Wikiversity.org: a 20-item self report measure of mood states on a 5-point Likert scale (1= very slightly or not at all, 5= extremely) (Watson, Clark & Tellegan, 1988). Items are divided into positive or negative, with ten items in each category. A score between 10 and 50 is possible in both categories. The mean score for positive affect is 35.7 (SD = 6.2) and for negative affect is 19.5 (SD 6.0) (Watson & Clark, 1994). This measure is used with one of seven different time instuctions; at the moment, today, in the past few days, in the past week, in the past few weeks, in the past year, or in general (Watson, Clark & Tellegen, 1988). A longer version, the PANAS-X, contains not only positive and negative affect but also fear, hostility, guilt, sadness, joviality, self-assurance, attentiveness, shyness, fatigue, serenity and surprise (Watson & Clark. 1994). The PANAS-X is a 74-item self report measure on the same 5-point Likert scale as the original (Watson & Clark, 1994). Both measures were constructed so each item held high factor loading on the selected scale, such as positive affect, and near-zero factor loadings on all other scales (Watson, Clark & Tellegan, 1988). An example of the PANAS can be found here (see the bottom of the fourth page).
POSITIVE AFFECT: *interested *excited *strong *enthusiastic *proud *determined *alert *inspired *attentive *active
NEGATIVE AFFECT: *distressed *upset *guilty *scared *hostile *irritable *ashamed *nervous *jittery * afraid