3 Most Effective Personnel Selection Methods For Hiring

Struggling to identify the best candidates? You're not alone. 37% of UK employers have "hard to fill" vacancies (CIPD, 2024), and 73% of job applicants aren't even qualified for the roles they apply to (SparkHire, 2024).

The good news? Research has identified exactly which selection methods work best. Instead of relying on gut feelings, you can use scientifically proven techniques that consistently predict job performance and save you from costly hiring mistakes.

Quick comparison: Which method is right for you?

The winning approach? Most successful hiring teams use these methods together – assessments for efficient screening, interviews for final decisions.

Here's a fact that might surprise you: cognitive ability is the single best predictor of job performance across virtually all roles. Whether you're hiring graduates, technical staff, or managers, thinking ability directly impacts performance.

Every job requires problem-solving, learning, and decision-making under pressure. This is critical when one in three UK businesses make bad hires due to rushed decisions (Protocol, 2024). Ability tests measure exactly these capabilities.

The stakes? With UK hiring costs averaging £6,125 per employee (CIPD, 2024), you can't afford to get it wrong. Ability tests help identify top performers before you invest significant time and money.

Matching tests to what matters in the role

Different jobs demand different thinking skills. The key is choosing tests that mirror the mental demands of your specific role:

• Numerical Reasoning: Perfect for roles involving data analysis, financial decisions, or interpreting metrics
• Verbal Reasoning: Essential for positions requiring communication, report writing, or processing complex information
• Inductive Reasoning: Ideal for roles where people need to solve new problems or identify patterns
• Critical Thinking: Crucial for decision-making roles or positions requiring logical evaluation
• Error Checking: Vital for detail-oriented roles where accuracy is paramount

The most accurate approach combines multiple tests to get a complete picture of someone's cognitive abilities. This gives you confidence that candidates can handle the full range of thinking demands your role requires.

The beauty of modern assessment platforms? They make this entire process effortless.

With Test Partnership's platform, you simply select the most relevant tests from our comprehensive library, invite candidates to complete them online, and instantly review results to identify your strongest performers. No training required, no manual scoring, no guesswork.

Skills tell you what someone can do, but personality reveals how they will behave. Personality questionnaires uncover behavioural patterns that often make or break job performance.

This matters more than many realise. Bad hires can reduce team productivity by 72% (Brandon Hall, 2024), usually due to behavioural mismatches, not skills gaps. With 25% of UK workers leaving for better opportunities (Totaljobs, 2025), personality assessments help identify people who'll perform well and actually stay.

What personality questionnaires reveal

These assessments provide insights you simply can't get from CVs or interviews alone:

• Work style compatibility: How do they prefer to approach tasks and interact with colleagues?
• Stress resilience: How will they handle pressure and demanding situations?
• Team dynamics: Are they naturally collaborative or more independent?
• Motivation drivers: What energises them and keeps them engaged?
• Cultural alignment: Will their values and work preferences fit your organisation?

The result? You can predict not just whether someone can do the job, but whether they'll thrive in your specific environment and stay engaged long-term.

You probably already use interviews, but here's the key: structured interviews (same questions for every candidate) are powerful predictors of performance, while casual conversations aren't.

The difference is consistency. Unstructured interviews create unfair comparisons and unreliable results.

The time investment reality

Interviews are highly effective but time-intensive. With the average UK hiring time at 4.6 weeks (Totaljobs, 2025), much comes from interview processes.

Unlike assessments that candidates complete independently, interviews require substantial team investment:

• Planning time: Developing consistent, job-relevant questions
• Scheduling complexity: Coordinating calendars for multiple stakeholders
• Active participation: Your full attention during each conversation
• Evaluation process: Reviewing responses and making decisions

The smart approach to interviews

This is why successful hiring teams use interviews as a final-stage selection tool, not a screening method. By using assessments to identify your best candidates first, you can focus your interview time on the people most likely to succeed.

This approach transforms interviews from a time-intensive screening process into focused conversations with pre-qualified candidates. You'll have better discussions and make more informed decisions.

The research is clear: cognitive ability tests, personality questionnaires, and structured interviews consistently outperform other selection methods. While there are many other tools available, these three form the foundation of effective hiring.

The key insight for busy hiring teams? You don't need to implement everything at once. Start with the method that addresses your biggest pain point:

• Overwhelmed by unqualified applicants? Start with cognitive ability tests to quickly identify capable candidates
• Struggling with cultural fit and retention? Begin with personality questionnaires to understand behavioural patterns
• Want to improve interview consistency? Implement structured interview techniques for your final-stage candidates

Most successful hiring teams combine these methods strategically: using assessments for efficient early-stage screening and structured interviews for final decisions. This approach has helped UK businesses save millions in bad hire costs while significantly improving their quality of hire.