When someone talks about 'call screening', that means they are looking at who is calling on the phone and only allowing certain calls through. They are 'filtering out' the unwanted calls, but I've never heard it referred to as 'call filtering'. I would likely never say 'call filtering', but why? Despite feeling awkward, could I say 'call filtering' and still be correct?

Sorry, I am not a linguist, etymologists, or English language enthusiast so I probably shouldn't even be posting here, but none of the other StackExchange communities seemed appropriate. If possible, please respond in 'little words' so that I can comprehend the answer. (And yes, English is my first language so I have no excuse for any grammatical sins in this question :) ).

  • If you look up Merriam-Webster verbal sense 3 for 'screen', you will see that it is a synonym for 'filter'. I couldn't say why one word was chosen and the other rejected for 'call screening'; perhaps it sounds more professional and authoritative ('screening process' has been around for decades). Aug 13, 2021 at 19:01
  • The connotations are slightly different.
    – RonJohn
    Aug 15, 2021 at 6:10
  • Thanks to everyone for the answers. Y'all really get into this stuff; I never expected such thorough answers. I was about to mark one of the responses as the accepted answer, but I cannot tell which one is more correct than the others. May I just leave this without an officially accepted answer?
    – Joe Gibbs
    Sep 8, 2021 at 6:15

6 Answers 6


In addition to the interesting points already made, filter tends to be applied to collections, suspensions or other (usually non-human) groupings while screening tends to be applied to individuals, and in particular, to people.

  • Examples of things that might be filtered: coffee, collections of frequencies, types of material in fish tanks.

  • Examples of things that might be screened: passengers awaiting boarding, job applicants.

To my ear, filtering applies to the collection as a whole, while screening can apply to an individual, although typically in the context of that individual being one of many. For example, one doesn't take a single grain of coffee for filtering although one can speak of pulling aside an individual passenger for screening.

More to the point, though, is that applying the term filter to people in phrases such as "filter out the undesirables" tends to sound dehumanising.

At the time call screening was invented, "phones" were merely devices that mediated the communication between persons, and a phone call referred more to the person than the transmission. With rotary and early DTMF (push-button) phones, even the telephone number of the caller was not accessible to the recipient. If someone received a call, it would be more natural to wonder who it was than what number it was.

Caller-ID is said to have been prototyped in May 1976, and before that, it would have been normal to have secretaries (as opposed to devices) screen "calls" to busy bosses - whether the calls were by telephone or in person (someone 'calling by').

Taking all this together, at the time it would be more natural to think about screening each caller than filtering the list of incoming telephone numbers. Things are somewhat different today - it is more common now to think in terms of receiving unsolicited calls "from an unknown number" rather than "by an unknown person".


Yes, in this context 'screening' and 'filtering' are synonyms.

However, whoever first (it could have been a number of people) referred to this activity as 'call screening' at least in North America. It could just as easily been 'call filtering' but the arbitrary choice was made and 'screening' is what is usually used instead of 'filtering'. And now 'filtering' sounds weird only because it is so uncommon.

The metaphor of 'screening' (or filtering) is much older than 'call screening' so really the habit was established earlier.

So in the end, you don't want to use 'filtering' not because it is logically wrong (it's not wrong) but because there is a more common way to say it.

  • 1
    Moreover, given that screening is so well established, using filtering, even though correct in the abstract, could be confusing: it would make people wonder whether one is referring to call screening or to some similar, but not quite the same, process.
    – jsw29
    Aug 13, 2021 at 21:33
  • @jsw29 Yes, that is part of the implication of the strangeness of using 'filtering' - "Oh it must mean something different since people always say the other ni this instance." People are people, not logical machines.
    – Mitch
    Aug 13, 2021 at 21:59

If we look at some meanings of "screen" from the OED:

**2.b. transitive. To block or shut off (wind, the sun, etc.) by interposing an obstruction; to act as or form a barrier preventing (wind, the sun, etc.) from passing through.

Note the use of "blocking" that is not really covered by "filter"

1657 T. Watson Christs Lovelines in Saints Delight 390 How lovely is Christ who can screene off the fire of Gods wrath from thee.

2005 Age (Melbourne) (Nexis) 19 Feb. (Gardening section) 6 Planting trees and shrubs in groups also reduces maintenance because each group forms a self-supporting thicket that screens the wind.

II. To sieve, filter; to evaluate, analyse. 9. a. transitive. To obtain, remove, or separate (something, esp. impurities or unwanted material) from a substance, mixture, etc.,

1613 R. Loder Farm Accts. (1936) 50 iiij b. of seedes skrined out of my mault I value at xijs. viijd.

2010 I. Alesina & E. Lupton Exploring Materials 82 In India, cotton saris are used to filter water by screening impurities.

In the mid-20th century these old, established, uses gave rise to

11.c. transitive. To investigate or evaluate the suitability or eligibility of (a person, esp. as one of a group) for a particular purpose; to examine or check for the presence of a desirable or undesirable element or attribute.

1942 Cedar Rapids (Iowa) Gaz. 16 Oct. 18/6 USES work applicants are being carefully ‘screened’ by test to determine their abilities.

1956 W. Graham Sleeping Partner x. 82 When you said you were bringing an assistant to Harwell, of course we had to have her [security] screened.

1990 M. J. Heale Amer. Anticommunism vii. 138 Federal employees were to be screened for ‘disloyalty’, a concept that was not clearly defined.

It is this final meaning that has given rise to "call-screening".

I'm sure it is a commercial ploy to give the idea of some sort of security check. It has overtones of the "intelligence community and the military" giving the user of "call screening" the security that they think they want: A nuance that "filter" lacks.

  • If you buy screenings you get small pieces of crushed rock screened from the bigger pieces. This usage goes back at least to mid 20th century.
    – Peter
    Aug 14, 2021 at 1:18

'Filter' is used as an term in electronics for devices which only allow certain frequencies through, and there already are many such devices used processing calls. I suspect calling 'call screening' 'call filtering' would have have been ambiguous to the engineers, as it would be first understood as to do with applying filters to the audio content of the call not screening out certain calls.

  • This is unquestionably the correct answer. Telephony was in existence for many decades before radio. Filtering was of great interest, since the frequency response of telephone lines had an effect on the sound that could be reconstructed from the electrical signal. In the early studios used for live radio with call-ins, the sound technician at a mixing desk would do the filtering, and an operator at a switchboard would do the screening. Special circuits called “hybrids” were used to interface the 2-wire telephone circuits with the 4-wire circuits needed in the studio. Aug 16, 2021 at 18:24

From a programmer's perspective, screening and filtering do mean the same thing in this context.

In fact, one of the most basic forms of spam filtering (though admittedly long since rendered ineffective by spammers getting more creative) is to just check the sender's address with a list of known spammers and direct the message to the junk folder if it is. This is the exact inverse of what you do manually when you check the caller ID on your phone and let it go to the answering machine if you don't recognise the number and only answer it if you do.

  • 1
    People screen calls and programs have filters to filter them. In the end, the result can be the same but no one here seems to have pointed out this basic fact.
    – Lambie
    Aug 15, 2021 at 15:00

The term "screening" is also used by archaeologists/paleontologists in a literal sense: You put a bunch of dirt which might contain objects of interest into a actual screen - generally a 1/4" wire mesh in a wooden frame - and shake it to filter out all the dirt and leave only the larger objects: artifacts, bone fragments, etc. This usage goes back much earlier than the invention of telephones, and may be the possible analog they were thinking of when they came up with the term.

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