NAQT Invitational Series

IS Sets (short for Invitational Series) are 15-packet question sets produced by NAQT, typically for use at regular season high school quizbowl tournaments. Each packet consists of 24 tossups and 24 bonuses; the distribution is posted on naqt.com. Generally, each IS set is used by many different tournaments around the country on different dates during the school year. As of the 2010-11 season, NAQT produces six new IS-sets per year.

Introductory Invitational Series

NAQT also produces 12-packet Introductory IS sets, also known as "A-series" sets or A-Sets, because their designations end with the letter A (such as "IS #97A). These sets have shorter, easier questions than the regular Invitational Series and are intended for first- and second-year high school players. NAQT produces four new A-sets each year.

Reception

Until about 2008, some elite high school teams criticized IS Sets for being too easy, or for being funn. More recently, statistics-based inquiry has questioned whether IS-sets might be more difficult for local/low-level teams (see here). Despite this, IS-sets are a staple of many local high school quizbowl circuits, with overall reception being positive in recent years.

College tournament controversy

Many people prominent in the college game have criticized college tournaments for using IS sets. Their arguments include the fact that questions produced for high school players are inappropriate for a college audience, and that these tournaments might sap funds from tournaments aimed at college teams. See these threads for discussion of this issue.