From cold outreach to signal-based outbound in 5 steps

Cold outreach delivers less and less. The average reply rate on cold emails has dropped to 4-5% — and that number drops every year. Time for a different approach. In this article, I show you in 5 concrete steps how to switch to signal-based outbound.

Why cold outreach keeps getting worse

The numbers don't lie. The average reply rate on B2B cold emails dropped from 8.5% in 2019 to 7% in 2023 and further to about 4-5% in 2025. Every year it gets worse, and there are three hard reasons.

Overflowing inboxes. Decision-makers receive an average of 15 cold emails per week. 71% are ignored due to irrelevance. Your competitor sends the same template to the same list — and you're drowning together in the inbox.

Stricter spam filters. Google has lowered the spam threshold to 0.1%. That means: 1-2 complaints per 1,000 emails and your domain is in trouble. Apple's Mail Privacy Protection and Outlook's new filtering don't help either.

Buyer behavior has changed. B2B buyers do 70% of their research before they want to talk to sales. They expect relevance. A generic message about 'having a quick chat' no longer works — it irritates.

The top 10% of outbound campaigns still achieve 8-12% reply rates. The difference? Timing and relevance. And that's exactly what signal-based outbound is about.

What is signal-based outbound?

Instead of buying a list and sending everyone the same message, you flip it: you wait for a signal indicating someone is open to your solution, and only then do you reach out.

Those signals — also called buying signals or buyer signals — are concrete, observable events: a company raises funding, hires a new sales manager, visits your website, or switches technology. When you respond to something that just happened, your outreach doesn't feel like spam but like relevant help.

Step 1: Define your ICP more sharply

Most companies have an ICP that's too broad. 'B2B SaaS companies with 50-500 employees' is not an ICP — it's a market. For signal-based outbound you need to be sharper, because you'll build campaigns per signal type.

Firmographic: revenue, number of employees, industry, location, growth stage. This is the foundation you probably already have.

Behavioral: this is where most companies fall short. Add: what technology do they use? Are they growing? Are they investing in sales and marketing?

Write out your ICP in maximum 5 sentences. If you can't describe it in 5 sentences, it's too broad.

Step 2: Choose 3-5 relevant buying signals

You don't need to monitor all signals at once. Start with 3-5 signals most relevant to your business.

The rule of thumb: choose signals where you can actually attach a relevant opening line.

Step 3: Set up your monitoring

Now it gets technical — but not complicated. You need three layers.

Layer 1: Signal detection with Clay

Clay is the hub of your signal-based setup. You build 'tables' that automatically monitor triggers: new hires on LinkedIn, funding rounds via Crunchbase, technology changes via BuiltWith. Clay checks 150+ data sources and automatically enriches with company and contact data.

Layer 2: Website visits with Leadinfo

Leadinfo (Dutch, GDPR-compliant) shows which companies visit your website. Not who exactly, but which company, which pages, how often. Connect this to your ICP filter and you have a daily list of warm leads.

Layer 3: LinkedIn engagement with Sales Navigator

LinkedIn Sales Navigator (Advanced edition) has buyer intent built in. You see which contacts at your saved accounts visit your company page, like your posts, or accept your InMails.

The combination of these three — Clay for events, Leadinfo for website visits, Sales Nav for LinkedIn engagement — gives you a complete picture of which companies are ready now.

Step 4: Build campaigns per signal type

This is where most teams make a mistake: they capture all signals in one generic outbound campaign. Don't do that. Each signal type deserves its own message and cadence.

Use a tool like Instantly or Lemlist for execution. Both integrate with Clay, so you can load enriched data directly into your campaigns.

Step 5: Measure and optimize

Signal-based outbound is not 'set and forget.' You need to measure which signals actually convert — not just to replies, but to meetings and deals.

Measure per signal type:

• Reply rate (target: >10%)
• Positive reply rate (target: >5%)
• Meeting-booked rate
• Pipeline value per signal

What you'll probably discover:

• 1-2 of your 5 signals deliver 80% of results
• Timing makes more difference than copy
• The combination of signals (e.g., website visit + new hire) is stronger than individual signals

Optimize in this order:

1. Signal selection: stop with signals that don't convert
2. Timing: test whether responding faster makes a difference
3. Copy: A/B test opening lines per signal type
4. Channel: test email vs. LinkedIn vs. multichannel per signal

Review your data every 2 weeks. After 3 months you have enough data to streamline your setup to the 2-3 signals that truly work for your business.

Always compare with your old approach. If your cold outbound had a 3% reply rate and your signal-based campaign is at 12%, you know the extra monitoring time is worth it.

Conclusion: start with 1 signal type

You don't need to set up everything at once. The best way to start:

1. Choose 1 signal that's most logical for your ICP
2. Set up monitoring via Clay or Leadinfo
3. Build 1 campaign with a specific opening line
4. Measure for 4 weeks and evaluate
5. Only then add signal 2 and 3

The difference between cold outreach and signal-based outbound isn't the technology — it's the mindset. You stop sending to everyone and start listening to who is ready.