Should we always stress the benefits to be more persuasive?
Ask most people and you'll get the same response. (I've being asking for years.)
They'll favour positive arguments, stressing the benefits, over negative every time. Surely it's always best to be positive? Not so fast.
Negative arguments can be highly effective
It is good to point out the benefits, but negative arguments should be in your toolkit too. Just be a bit more careful with them.
Pointing out the risks of doing nothing or doing the wrong thing may arrest their attention.
Want to persuade your senior management team to buy new software? Try, 'The cost of the do-nothing option is likely to be $X within a year.' Then provide your evidence. That's a good service.
The cost may not be dollars and you may not be able to provide hard evidence, but you could suggest problems ahead, say inefficiencies, higher staff turn-over, possible loss of market share or compromised customer service. You might point out the opportunity cost of spending the budget on one thing and missing out on another.
Even if you can't provide hard evidence, provide what you can, upfront, before they ask for it. Make sure your solution overcomes at least the major risks.
Why emphasise the negative?
Decades of research shows that we fear a loss more than we value a gain. An example: Researchers at the University of California found that 300 per cent more homeowners agreed to improve their energy efficiency if they were told it would stop them losing 50 cents a day, rather than saving 50 cents.
Your audience or readers may not mention their fears of loss, but those fears will be running through their minds.
Why take care with negative arguments?
Lay on the negative consequences of not adopting your recommendation too thickly or without justification and your audience will see it as manipulation or pressure.
You need their trust. Easy does it.