Why Phishing Campaign Difficulty Matters and How to Use the NIST Phish Scale for More Effective Training

GenAI-powered phishing emails trick 60% of recipients—matching the success rate of traditional attacks (Harvard Business Review). This highlights a growing challenge for security teams: modern phishing campaigns are not only more deceptive but also more effective.

Phishing has evolved from obvious scams to highly targeted, AI-enhanced attacks that can easily bypass standard training defenses. To stay ahead, organizations must move beyond generic awareness programs and adopt adaptive phishing simulations tailored to each employee’s role, risk profile, and behavior.

In this blog, we’ll explore why phishing difficulty matters, how to apply the NIST Phish Scale to better measure and refine your simulations, and how Keepnet’s AI-powered Phishing Simulator helps deliver smarter, personalized training that actually changes behavior.

Why Phishing Simulation Difficulty Matters

Most phishing training still relies on generic, one-size-fits-all simulations—a method that doesn’t reflect the sophistication of modern phishing threats. As a result:

• Employees lose focus when emails are too easy, leading to overconfidence.
• They become discouraged when simulations are too difficult, especially if they feel unprepared.

To be effective, phishing simulations must strike the right balance—challenging employees at the right level to keep them engaged and improving.

A Smarter Approach: Matching Simulations to Skill Levels

Effective phishing training can’t rely on uniform simulations for every employee. People have different levels of awareness, experience, and risk exposure—so their training must reflect that. By gradually increasing simulation difficulty based on individual performance, organizations can:

• Keep training relevant and engaging: Employees are more likely to stay focused when simulations match their skill level.
• Develop layered detection skills: Exposure to a wide range of attack styles—from basic to advanced—helps employees recognize threats more effectively.
• Avoid burnout or frustration: Tailoring difficulty levels keeps employees challenged without overwhelming them—avoiding both boredom and frustration.
• Drive measurable behavior change: Employees progress steadily, making fewer mistakes over time and becoming more proactive in spotting threats.

This adaptive model turns training into a continuous learning journey—keeping employees sharp and your organization better protected.

How to Define Difficulty in Phishing Scenarios

Phishing email difficulty is influenced by three core elements: polish, context, and clarity of warning signs. These factors determine how easily—or not—an employee can recognize a phishing attempt during a simulation.

• Polish: Well-written, error-free emails appear more legitimate and professional, making them harder to question.
• Context: Messages that align with the recipient’s role or reference recent internal or external events seem more believable.
• Clarity of Warning Signs: Emails with fewer clear red flags—such as suspicious links, strange formatting, or urgent tone—are significantly harder to detect.

Consider how these elements affect difficulty:

• Simple Example: A poorly written “Your Account Is Locked” email, filled with typos and linking to a suspicious, unfamiliar URL.

• More Difficult Example: A clean, well-branded message from “IT,” referencing a recent software update and embedding a malicious link that closely resembles a legitimate one.

These factors help create realistic simulations that sharpen employees’ ability to spot and respond to phishing threats.

Introducing the NIST Phish Scale: A Framework for Measuring Phishing Email Difficulty

The NIST Phish Scale, developed by the National Institute of Standards and Technology (NIST), is a research-based framework that helps assess how difficult a phishing email is to detect. Unlike basic click-rate metrics, it offers deeper insight into why employees fall for certain emails by analyzing context and content.

How the NIST Phish Scale Works

The NIST Phish Scale measures how hard it is for someone to detect a phishing email. It does this by evaluating two key elements: the visibility of phishing cues and how relevant the email feels to the recipient. These factors help explain why some emails are more convincing than others.

1. Cues in the Email

Cues are the visible signs that help users judge whether an email is suspicious or legitimate. The NIST Phish Scale organizes these cues into five key categories:

• Errors: Typos, grammatical mistakes, or awkward sentence structure
• Technical Indicators: Suspicious sender addresses, misleading or lookalike URLs
• Visual Presentation: Fake or outdated logos, inconsistent formatting, poor design
• Language & Content: Urgent tone, threatening language, or requests for sensitive information
• Common Tactics: Impersonation of trusted individuals or brands, fake rewards, or alarming notices

The fewer these cues appear, the harder the email is to detect as phishing.

2. Premise Alignment (How Relevant the Email Feels to the Target Audience)

Premise alignment refers to how closely a phishing email matches the recipient’s role, responsibilities, or current context. The more relevant the content, the harder it is to recognize as a threat. The NIST Phish Scale evaluates this based on factors like:

• Familiar processes: Does the email mimic real workplace tasks? (e.g., HR updates, invoice approvals)
• Role relevance: Is the content tailored to the recipient’s job? (e.g., finance staff receiving vendor requests)
• Timeliness: Does it reference current events or seasonal activities? (e.g., tax season, company audits)
• Emotional pressure: Does it trigger concern or fear of consequences? (e.g., payroll delays, account lockouts.
• Training exposure: Has the employee been trained on similar scams?

The more aligned the email is with the user’s expectations, the more difficult it becomes to detect.

How to Apply the NIST Phish Scale to Phishing Simulations

Organizations can strengthen their phishing training by using the NIST Phish Scale to design more realistic and targeted simulations. Let’s explore how you can apply it effectively in your training program.

Step 1: Analyze Employee Roles & Risk Levels

Phishing risks vary by role. Executives like CEOs or CFOs are common targets for Business Email Compromise (BEC) attacks, while IT staff are more likely to receive phishing emails disguised as software updates or internal requests. Tailoring simulations to each role ensures relevance and increases training effectiveness.

Step 2: Categorize Phishing Email Difficulty Using the NIST Phish Scale

Use the NIST Phish Scale to look at how obvious the warning signs are and how relevant the email feels to the employee—then sort each email into one of three difficulty levels. The table below shows examples of each level to help guide your categorization.

Table 1: Phishing Email Types Categorized by Difficulty Level

This categorization helps deliver simulations that are both realistic and aligned with employee skill levels.

For a deeper dive into personalized, adaptive training strategies, check out Keepnet’s AI-Powered Hyper-Personalized Security Awareness Program—a strategic guide to designing role- and risk-based simulations that actually change behavior.

How Keepnet Uses the NIST Phish Scale to Improve Training

Keepnet integrates the NIST Phish Scale into its AI-powered Phishing Simulator to deliver adaptive, risk-based phishing awareness training. Instead of random testing, employees are challenged based on their role, risk level, and simulation history.

Phishing emails are categorized by difficulty and relevance, ensuring each simulation is realistic and role-specific. With over 6,000 regularly updated templates, localized and tailored by tone and context, Keepnet makes phishing simulations both personalized and effective.

1. Dynamic Difficulty Adjustment with AI

Traditional phishing simulations often follow a generic approach—sending the same email to all employees. However, real attackers tailor their phishing tactics based on the target’s role and exposure. For example, a customer support agent might receive fake customer complaints, while a finance employee could face invoice scams. This mismatch reduces training effectiveness.

Keepnet’s Solution

Keepnet solves this by using AI and the NIST Phish Scale to adjust difficulty levels in real time, ensuring each employee receives relevant, personalized training. The system considers:

• Employee awareness level: Phishing difficulty is scaled to match user experience.
• Updated phishing templates: Over 6,000 real-world email scenarios are refreshed regularly to reflect current threats.
• Cultural localization: Emails are adapted to each region’s language, tone, and formalities for added realism.

Table 2: Phishing Simulation Examples by Role

As a result, employees get realistic, role-based simulations that mirror the phishing threats they’re most likely to face—improving engagement and retention.

2. AI-Driven Risk-Based Customization

Phishing threats vary widely across departments. Finance teams are prime targets for invoice fraud, while HR staff may receive scams related to payroll or hiring. Generic training misses these role-specific risks, leaving critical gaps in employee preparedness.

Keepnet’s Solution

Keepnet’s AI Phishing Simulator customizes each training experience by analyzing employee role, behavior, and risk level. It ensures employees receive phishing emails that reflect their actual exposure. Key features include:

• Function-specific scenarios: Simulations mirror real tasks based on job roles.
• Localized phishing content: Templates are translated into 36+ languages and adapted to reflect local threats and cultural context.
• Smart template matching: AI selects from over 6,000 regularly updated phishing templates, keeping simulations relevant and realistic.

Table 3: Phishing Examples by Risk Level in Finance

By tailoring training to each role and risk profile, Keepnet delivers high-impact simulations that boost employee readiness and reduce the chance of successful phishing attacks.

3. Continuous Learning with Real-Time Feedback

Most phishing training programs track clicks or reports—but stop there. Without immediate, actionable feedback, employees don’t understand what they missed or why a message was suspicious. As a result, key learning opportunities are lost.

Keepnet’s Solution

Keepnet’s AI Phishing Simulator delivers real-time feedback the moment an employee interacts with a phishing simulation. This turns every click or report into a learning experience:

• If an employee clicks: They receive a clear explanation of the red flags they overlooked.
• If they report the email: They get positive reinforcement and a breakdown of what they caught.
• For security teams: Detailed analytics show progress across individuals and departments over time.

Table 4: Password Reset Request Simulation

With real-time feedback, employees actively learn from each simulation—sharpening their judgment and improving long-term phishing resistance.

4. Scaling Phishing Simulations Across a Global Workforce

Global organizations operate across regions, languages, and cultures. A phishing email written in English may not resonate—or even make sense—for employees in non-English-speaking countries. Generic simulations risk being unrealistic and ineffective.

Keepnet’s Solution

Keepnet’s AI Phishing Simulator supports global scalability with over 6,000 dynamic templates localized in 36+ languages. Simulations are tailored to match each region’s language, tone, and cultural expectations. This includes:

• Language localization: Emails are translated and formatted to feel native to each recipient.
• Cultural context: Training reflects phishing tactics common in specific regions or industries.
• Tone adaptation: Formal or casual tones are adjusted based on local communication norms.

Example:

A CEO impersonation email in Japan may use formal language, while in the U.S., it’s written in a more casual tone. Keepnet adapts both versions to appear authentic and relevant to their respective audiences.

Training feels real, no matter the employee’s location—making phishing awareness scalable, inclusive, and effective worldwide.

For deeper insights on building impactful phishing programs, check out Top 10 Questions for Effective Phishing Simulation in 2025.

Phishing Email Examples Tailored by Difficulty

To illustrate how phishing difficulty can vary, here are 3 versions of a fake “Outlook Update Notification” email—each crafted for a different user awareness level.

Easy Difficulty Example

This example is easy to recognize as a phishing email, making it perfect for training employees who are just getting started.

Why It’s Easy:

This phishing email contains several obvious red flags, making it ideal for training beginners to recognize basic phishing tactics:

• Typos like “Updte” and poor grammar (“Your Outlook need...”) are easy to spot
• The domain (@ms-outlook.net) is clearly fake and doesn’t match Microsoft’s real domain
• The urgency ("lock your account") is exaggerated and feels unnatural

Perfect for users who are just starting to learn how to identify phishing attempts.

Medium Difficulty Example

This phishing email is crafted to look more believable, making it a good challenge for users with basic awareness. It avoids obvious mistakes but still includes small warning signs that can reveal its true intent to a trained eye.

Why It’s Medium:

This email is designed to appear legitimate at first glance, but it contains small inconsistencies that require a trained eye to catch. It's a good test for users with basic phishing awareness.

• The sender domain (@msoutlook.com) closely resembles a real one but is slightly incorrect
• A small typo in the body text (e.g., “required” repeated) can easily go unnoticed
• The 48-hour deadline creates a sense of urgency without sounding too aggressive

This level encourages users to pay closer attention to subtle warning signs in otherwise well-crafted emails.

Hard Difficulty Example

This phishing email is designed to closely mimic a legitimate communication, making it difficult to detect without careful inspection. It’s ideal for advanced users who need to identify well-crafted, deceptive messages.

Why It’s Hard:

This email is designed to appear fully legitimate, making it difficult to detect as phishing even for trained users.

• The domain (@microsoft-outlook.com) looks nearly identical to the real one
• The email is clean, professional, and free of obvious errors
• The call-to-action is subtle, with no exaggerated urgency

This level is intended to sharpen advanced users’ skills in spotting high-quality, deceptive phishing attempts.

Smarter Training for a Stronger Defense

Adaptive phishing simulations aren’t just a training upgrade—they’re a strategic advantage. For organizations, they lead to sharper threat detection, fewer successful attacks, and deeper insights into human risk. For employees, they provide tailored challenges that build real skills, boost confidence, and keep engagement high.

With phishing attacks growing more targeted and harder to spot, outdated training methods fall short. AI-powered, role-based simulations—guided by the NIST Phish Scale—offer a smarter, scalable, and measurable way forward.

With Keepnet’s AI Phishing Simulator, you can deliver personalized, real-world scenarios that prepare your team for the specific threats they’re most likely to face. This leads to a well-prepared workforce that can spot threats early and a stronger, more secure organization.