Simple definitions of terms commonly used by radio reps.

Average Frequency is the number of times the average person has heard you over a specific length of time. REACH x FREQUENCY = GRPS . If you buy four or five stations and get a "70/3 TA R/F" that means you reach 70% of the Target Audience in the market 3 times each, which multiplies out to 210 TA GRPS. 

Average Quarter Hour (AQH) Audience is the number of persons listening for at least 5 minutes during a quarter hour in any given day part. Some stations quote AQH in hundreds. "AQH 100" usually means "10,000 persons listen to the average spot in this day part."

Cash In Advance (CIA) invoices bill a client or agency for the net or gross amount of a contract.  The spots run if the station gets the money, usually by the Thursday preceding the flight week.

Cost Per Thousand (CPM) impressions varies with audience size and advertiser demand.  Most stations in a market charge a competitive CPM for Persons 12+ or 18+, but they'll set their spot rates to reflect agency and advertiser demand for the demo they reach best.

Cume, Weekly is the number of discrete persons who listen to the station for at least 15 minutes between Monday at 6am and Sunday at midnight. A station's cume rating is its percentage of local population. "Cume Rtg 12" means the station reaches 12% of the market each week. 

Cume Ranker is a list of local stations ranked according to the number of people in the weekly cume who conform to your Target Audience or Qualified Audience specifications. Rankers usually show the market population TA and QA and offer a cume rating for each station.  Some rankers list stations in order of TA or QA AQH.

Day Parts are parts of the broadcast day.  The common day parts are

   Mon-Fri: 5a or 6a-10a; 10a-3p; 3p-7p or 8p; 7p-12M, 12M-5a. 
   Sat & Sun: 6a-12N; 12N-8p; 8p-12M.

Duplication or Audience Duplication (AD) is the percentage of one station's weekly cume that also listens to another station. If WABC has a weekly cume of 100,000 and an AD of 15% with WDEF, then 15,000 WABC listeners also listen to WDEF.  AD is usually computed for P12+ or P18+ and is rarely available for tighter TAs or QAs.

Gross Impressions (GIMPS or GIs)/font COLOR="#121C59"> are the total number of hits. If one person hears you three times, that's three GIMPS or GIs.

Effective Frequency (EF) is the number of times half or more of a station audience hears your commercial during a given period of time.  (# Spots / Turnover) x .911 = EF

Fixed Position/font COLOR="#121C59"> commercials are guaranteed to run within a specific day part such as Mon-Fri 6a-10a. 

Gross Rates are the retail prices of commercials.  Agencies normally earn a 15% commission on gross.  Some prices (e.g. Streaming) are quoted at net rates.  Agency commission is NET x 17.65%.

Gross Rating Points (GRPs) are percentages of the the total market. "15 GRPS" is a number of GIMPS equal to 15% of the market population. Target Rating Points (TRPs) are percentages of the market Target Audience population.

Loyal Audience (P1s)/font COLOR="#121C59"> is the group of persons who Prefer a given to all others in the market, normally about 70% of weekly cume. P2s prefer the station to all others but one. Some stations track Exclusive Cume, people who listen ONLY to that station. 

Make-Goods occur when a spot you buy does not run, for whatever reason.  The station runs later on in the same day part.  If your campaign is time-sensitive you can take a cash rebate instead.

Media Cost Per Sale (MCPS, X) is the gross media cost of a final sale or lead. The selling price of most 1-800 AMAZING widgets includes ±20% for manufacturing, ±10% for overhead, and 38% to 55% for gross media.  Dot-coms do better if MCPS is in the 22% to 38% range. Creative, production. telemarketer training, etc. are overhead costs that must be amortized over time. Variable TM fees and commissions can be included in media cost.  Shipping & Handling, credit card fees, etc. are not media costs.  CICO (Cash In : Cash Out) tracks dollars. GM/C=X tracks response rate, media cost and conversion rate simultaneously.

Net Rates are 85% of Gross. Some media costs, such as Streaming Radio and newspaper display rates are often quoted at Net.

Qualified Audience (QA) is defined by metrics similar to those use by the U.S. Census.  You can probe for income, education, presence of children, or dogs!...even residential ZIP Code.

Optimum Effective Frequency (OEF) is a range of Effective Frequencies in which most of your response occurs.  Derived by inspection from weekly reviews of EF and actual response data.

Optimum Effective Scheduling (OES) is an Arbitron idea. To achieve an Effective Frequency of, say, 3 in a given day part or week, buy a number of spots equal to Turnover x 3.3. 

Per Inquiry (PI) commercials earn commissions on the leads or sales generated.  Buyers can call a 1-800 number assigned to the station, or click to a monitored version of your URL.

Pre-Emptible Spots (IP & PP)  are sold at "REMNANT" rates. They run as scheduled unless some other advertiser is willing to pay a higher rate. Immediately Pre-emptible (IP) spots can be bumped by anyone.  Premium Pre-emptible (PP) spots can only be bumped by someone willing to buy at Fixed Position rates.

Ratings are station statistics reported by Arbitron, Qualitap, Tapscan, Media Audit, Radar, etc. They are derived from diaries kept by local listeners.  Ratings are fairly accurate for large stations in major markets. 

Reach is the total number of people who hear you one or more times. Reach can be expressed in numbers, percentage of station cume, or percentage of the market population.

Run of Station (ROS) is a flight plan in which you agree to buy  a certain number of spots, often called "Rotators," within a broad time period (e.g. Mon-Fri 6a-8p), for a discount price.  The station runs them at any convenient time.   Most stations will try to give you even exposure throughout the time slot. 

Streaming radio comes from a station website to a self-contained audio player or one on your computer.  A great many stations stream their broadcasts.  They usually reach 3% to 12% of their cumes but they can't run spots that use AFTRA talent, so Arbitron will not rate streaming audiences. I did figure out a way to accurately estimate GIMPs, AQH and CPM from streaming buys.  It relies on station Webmaster data, though.

Target Audience (TA) is normally defined by gender and age ranges. The normal splits are
Males, Females, or Persons aged [12+, 18-24, 25+, 25-34, 35+, 35-44, 45+, 45-54, 25-54, 55+ and 65+].

Turnover (Δ) is cume divided by AQH. This the number of times the AQH audience has to refresh itself to add up to the weekly cume. Low Δ stations (News Talk, Country, Gospel) have loyal audiences and require fewer spots to achieve any given frequency. High Δ stations (Hot AC, Top 40) often share their audiences. At the end of a tune, listeners push a button for a new tune, avoiding your message.

All of these numbers are available for all Arbitron-rated stations. There is a way to estimate cume, AQH etc. for tiny, unrated stations that sell Morning Drive :60s for $8.50.  But why buy them?