From the number alone, you can't. That's the honest starting point, and most of the shortcuts people use are unreliable.

A local area code doesn't mean local — spoofing a number in your own area code is the standard technique, and therapists describe exactly that, calls from different numbers in their own area code every day. A short silent voicemail doesn't mean spam either, though it usually is; one practitioner gets a five-second silent message every morning between eight and nine, always from a new number in the same range.

What does work is changing the question. Instead of trying to classify a call after the fact, make the caller leave something classifiable — a voicemail with words in it, a reply to a text, a booking. Spam almost never does any of those. A person who wants an appointment usually will, if you tell them clearly what to do.

So the practical answer has two parts: a greeting that asks for something specific, and a written reply to missed calls that lets a real person identify themselves without you having to phone them back.

What signals are actually worth anything?

A voicemail with content in it. The single most reliable signal available. Automated calls either leave nothing or leave silence. A person saying their name and what they're calling about is a person.

A reply to your text. Second most reliable, and it costs the caller almost nothing.

Repetition from the same number. Real people call twice. So do some automated systems, but the ones therapists describe rotate numbers rather than repeat them — a new number every morning is a machine, three calls from one number over two days is more likely someone trying to reach you.

Time of day, weakly. Business hours mean little. Calls at odd hours from unknown numbers skew heavily one way.

Things worth nothing: the area code, whether it looks like a mobile, and whether the call was short.

Why does a transcript help so much?

Because it converts an unknown into a decision you can make in eight seconds between clients.

The reason most therapists don't check voicemail promptly isn't indifference — it's that listening to a voicemail requires putting the phone to your ear, which you cannot do in a session or a waiting room, and which you have to do for every message including the silent ones. Reading is faster and can be done anywhere.

Once messages arrive as text, the sorting problem largely disappears. A silent message is visibly empty. A sales call announces itself in the first line. A person saying they were referred by their doctor and are looking for someone who works with anxiety is unmistakable.

This does not reduce the number of spam calls at all — that's a separate and harder problem — but it does remove the cognitive load of not knowing, which is most of what makes this exhausting.

What should the greeting say to help me sort?

Ask for specific things, in a specific order, and keep it short.

Something like: you've reached the practice, I'm in session during the day, and I return calls at a set time. Then the request that does the sorting — please leave your name, a number, and one sentence about what you're looking for.

That last part is the sorting mechanism. A caller who does it has identified themselves; a caller who doesn't has told you something too.

If your policy is that you don't return calls without a message, say that too. Practitioners who do this report that it works and that nobody is offended, because the alternative — silence and no explanation — is worse.

Is there a way to just block the spam?

Not cleanly, and anyone who tells you otherwise is selling something. The numbers rotate faster than you can block them, and the filters that catch machines also catch people.

Which makes triage the realistic goal rather than elimination. Reduce the number of unknowns you have to think about, accept that the volume itself is largely out of your hands, and make sure the real people have an obvious route through.

What does this cost me if I get it wrong?

In the direction of over-filtering: missed referrals you will never know about. One practitioner describes a person in crisis who called more than forty therapists over three months and heard back from four.

In the direction of under-filtering: your time, and the low-grade attrition of answering a line that is mostly nonsense. One therapist describes starting out answering every call possible and answering fewer and fewer as spam built up, which is how a practice line quietly stops being an intake channel.

Both errors are real. The written-reply approach is attractive mainly because it is cheap in both directions — it costs nothing when you're wrong about spam, and catches the person when you're wrong about a prospect.

The short version

Stop trying to identify callers from the number. Make the greeting ask for a name and a sentence, get your messages in a form you can read rather than listen to, and reply in writing to anything that left no message.

About Rivet

Rivet is a Canadian practice line built for therapists — a separate number for calls, texts and voicemail, with video sessions and clinical tools in the same place. Your data stays in Canada, and transcription runs on Rivet's own hardware rather than a third-party AI service.

One plan, $65 CAD a month, everything included. Fourteen-day trial, no card.

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