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." See TSL.

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.  CPM is more useful than CPP for tracking results and translating them into future expectations in other markets.

Cost Per Point (CPP) is the approximate cost of a number of gross impressions equal to 1% of a Target Audience.  If a million people live in a market, one Gross Rating Point is 10,000 impressions, not 10,000 unique listeners (some people will hear you more than once!).  In a market of 2.5 million, one GRP is 25,000 impressions.  Since "point" means different quantities in different markets, CPP doesn't work very well to plan future buys elsewhere from actual results here.  CPM is more useful. To derive CPM from CPP, divide CPP by [Local TA Population/100,000].

Cume, Weekly is the number of discrete persons who listen to the station for at least 5 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.  On average, 70% of a station's weekly cume listeners are P1s - they prefer that station to all others in a market.  If you buy, say 20 :60s on a station, most will be heard by P1s, a few by P2s and one or two by P3s.

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.

DMA (Designated Marketing Area) is the geographic area in which the residents receive the majority of their television broadcast signals from network affiliates located in the central city or cities. DMAs are a bit like dinosaurs these days in that most people get their TV from cable or satellite CTVOs.  However, the ZIP Codes in a DMA house most of the people who hear radio broadcasts.  If you can track sales by ZIP Code Cluster (say the 91 ZIPs in the Abilene DMA, you can quickly see how well a spot or remnant buy in a market produces results.

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) are the total number of hits. If one person hears you three times, that's three GIMPS or GIs.  If three persons hear you once each, that's also three GIMPS.

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 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. (Reach % x Frequency) x 100 = GRPS.

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 an incremental sale, customer or lead.  It is also the media percentage of gross revenues.  MCPS can be $10.00 on a $19.95 1-800 AMA-ZING Widget.  MCPS might also be 22% of $3.5MM in gross revenues. Target MCPS and Actual MCPS vary.  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. OEF Range is the entry and exit points of a run of commercials during which you achieve maximum response.  OEF Flighting is the time lapse - usually in weeks - between flights sufficient to achieve your OEF Range.

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.  Turnover = Cume/AQH.

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.

P1, P2, P3... refers to listeners who "Prefer" a station to all others, all others but one, all but two, etc.   P1s listen to a given station more than any other, according to Arbitron data and are normally 70% of a station's weekly cume.  P2s are 22%. P3+s are the rest. "Exclusive Cume" refers to the 5% to 15% of persons in the weekly cume who listen only to a given station. Radio advertising reaches mostly P1s. The terms can also be applied to a brand's exclusive, loyal, occasional and infrequent customers.

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.  About 5,300 FM stations and 1,800 AM stations stream their live broadcasts and reach 7% to 22% of their weekly cume through computers rather than terrestrial receivers.  About 15% of a terrestrial station's streaming cume often comes from outside the market.  There are also about 2,500 pure play stations that deliver their programming only via the Internet.  Commercials that run during a streamed program can be accompanied by banners that link directly to an advertiser's landing page.  See Streaming Radio for ideas on how to track clicks from landing page to shopping cart.

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+].

Time Spent Listening (TSL) is the number of hours the average listener spends with a station during a given day part. The longer the TSL, the fewer the spots you need to buy to reach listeners at a target frequency.

Arbitron defines TLS as: (# Quarter Hours in a Day part x AQH) / Cume Audience in that day part. If the Mon-Fri 6a-10a AQH is 25,000 and the cume is 125,000 then TSL = ([4 hours x 4 quarters x 5 days: 80 QH] x 25,000)/125,000 = 16 hours.

Arbitron uses average TSL and weekly cume to define AQH using simple arithmetic:  AQH = TSL x (cume/#QH).

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?