Paying only for results is an attractive proposition and a change of incentive rather than a removal of one. Whatever the result is defined as becomes the thing the supplier optimises for, including the parts of it you did not intend, and the faster route to most SEO results is the riskier one. Performance pricing can work, in narrow circumstances that are worth naming, and it fails in ways that are predictable from the structure.
Define the result and you have defined the behavior
Paid on rankings, the supplier will chase rankings including for terms that do not convert. Paid on traffic, it will chase traffic including from audiences that never buy. Paid on leads, it will widen the form. Paid on revenue, it needs access to data you may not want to share and a long enough window to be fair. Every definition produces a behavior, so choose the definition by asking what behavior you want rather than by which number is easiest to read.
Speed is the incentive, and the fast routes carry the risk
A supplier paid on outcome is paid sooner if the outcome arrives sooner, and the methods that produce rankings quickly are disproportionately the ones Google's spam policies name, including links exchanged for money. Your domain carries that risk and the supplier does not. Ask explicitly whether any link acquisition involves payment or exchange of value, get it in writing, and make it a termination clause rather than a preference.
Attribution decides who gets paid, so agree it before anything starts
Under performance pricing, the attribution question stops being an analytical debate and becomes an invoice. Agree what counts, what window applies, whether branded search is included, and who owns the measurement system, before the first month. Disputes here are the most common way these arrangements end, and they end badly because both parties believe they are owed.
Where it genuinely works
As a bonus on top of a fair retainer, tied to a commercial outcome you both trust, over a window long enough that luck averages out. That structure keeps the supplier funded enough to do careful work and rewards the outcome you actually want. It also survives a bad quarter, which a pure performance arrangement usually does not, because the supplier simply stops working the account.
What happens when the target is reached
Ask this in the first meeting, because most performance agreements are silent on it. If the supplier is paid on reaching a position, what is the incentive to hold it, or to keep improving anything else. If they are paid monthly for maintaining it, you have a retainer with extra steps and a metric that may no longer be the right one. A good answer describes what the arrangement becomes next; a vague one describes an arrangement that ends in an argument.
Questions people ask about pay per result SEO
Is pay per result SEO cheaper?
Not usually, once it works. The supplier prices in the risk of being paid nothing, so the rate when results arrive is higher than a retainer would have been. What it changes is when you pay and who carries the risk of failure, which can be worth a premium for a business that cannot fund a speculative retainer.
What should the result be defined as?
Something commercial that you can both see and that the supplier can plausibly influence: qualified enquiries or sales from non-branded organic traffic is usually the least gameable. Rankings are the most gameable, and traffic sits in between. Write down the definition, the window, the exclusions and who measures it before any work starts.
Is it safe for my website?
It depends entirely on method, and the structure pushes towards speed. Require in writing that no link acquisition involves payment or exchange of value, ask what the supplier would refuse to do, and keep the right to audit the link profile. Those three make the arrangement much safer without changing the pricing at all.
What is the better alternative?
A fair retainer with a modest performance bonus attached to an agreed commercial outcome, and a short initial term so that leaving is cheap if it is not working. That gives you most of the alignment with none of the incentive to take risks with an asset you cannot replace.