NAQT Invitational Series
Invitational Series is NAQT's standard product for high school invitational tournaments. Popularly known as IS Sets, they are 12-packet (formerly 14- and 15-packet) question sets in which each packet consists of 24 tossups and 24 bonuses according to this category distribution. Generally, each IS set is used by many different tournaments around the country on different dates during the school year. Recently NAQT has produced five new IS sets per year.
Sets are numbered consecutively. Invitational Series #201, or IS-201, was the last set for the 2020-2021 competition year.
As with all NAQT products, IS tossups are limited in length. The current limit is 425 characters (with some arcane rules about which characters count).
Introductory Invitational Series
NAQT also produces Introductory Invitational Series sets, commonly called A-sets because their numeric designators are followed by "A" (e.g. "Invitational Series #200A" or "IS-200A"). These sets have easier, shorter (maximum 291 characters) questions and are intended for beginning high school players, and use a slightly different category distribution. Recently NAQT has produced five new Introductory IS sets per year.
NAQT shares questions between Invitational Series sets (including introductory sets) and custom offerings, such as questions for the unique MSHSAA and IHSA formats, and in 2015-2016 and earlier, questions for TV shows. The corresponding IS sets then become unavailable in the target market for the custom sets.
In 2016–2017, the fifth regular IS set of the year (IS-166) used some questions modified from the same year's Division II Sectional Championship Tournament set. This had also been done in some form a decade prior. In 2017–2018, NAQT discontinued the fifth regular IS set of the year, offering hosts the unmodified Division II SCT set instead.
Since about 2010, IS sets have been well received, though in the previous decade reviews were more commonly negative. Late-season IS sets are sometimes criticized as being too difficult due to NAQT's practice of trying to minimize repeats between IS sets in the same year. Some analysis was done of difficulty in 2011.
Number of Packets
At the beginning of the IS program (1997), regular IS sets were 15 packets (usually of 24/24) long.
In 2011–2012 NAQT switched regular sets to 14 packets (of 24/24) since almost no tournaments used all 15 packets.
In 2016–2017 NAQT switched regular sets to 12 packets (of 24/24) and introduced alternate versions in which there were 13 packets of 22/22.
Introductory Invitational Series sets have always been 12 packets long (also of 24/24) except for the very first set (IS-36A), which was 15 packets long. When the 13-packet, 22/22 versions of regular sets became available in 2016-2017, the same offering was made for Introductory Invitational Series sets for the first year only.
When the IS program began in 1997, the sets were intended for college tournaments. At some point shortly after that, they became a high school product. In the 2000s some IS sets were used for college tournaments, a widely criticized practice. In the 2010s this practice became very rare. In 2015-2016 NAQT began producing a Collegiate Novice Series, in which one regular Invitational Series set (and sometimes one Introductory Invitational Set) per year would be modified into NAQT's college category distribution, with new questions added to be suitable for a college audience.