Concerns about fairness create other pressures when designing comp plans. For instance, companies realize that success in any field, including sales, involves a certain amount of luck. If a rep for a soft-drink company has a territory in which a Walmart is opening, her sales (and commission) will increase, but she’s not responsible for the revenue jump—so in essence the company is paying her for being lucky. But when a salesperson’s compensation decreases owing to bad luck, he or she may get upset and leave the firm. That attrition can be a problem. So even though there are downsides to making a compensation system more complex, many companies have done so in the hope of appealing to different types of salespeople and limiting the impact of luck by utilizing caps or compensating people for inputs or effort (such as number of calls made) instead of simply for closing sales.