19 The essential purpose to which I refer is to provide the defendant, without prejudice to its case if the offer is not accepted, with some measure of protection against an order that it pay the costs of the action of both parties. The total of damages and costs commonly amounts to a considerable sum of money following a trial, particularly in the case of actions by workers against employers for damages for personal injury. When determining what amount to offer, a defendant will commonly weigh up its risk so far as liability is concerned and the likely assessment of damages, thereby arriving at the likely judgment sum, and the costs the parties may incur after the date of making the offer. The amount of the offer will frequently need to be sufficiently high, but not excessively so, to tempt the plaintiff to accept it, rather than incur the risk of being ordered to pay substantial costs in the event of the judgment sum following a trial not exceeding the offered amount. It is the relationship between the sum offered and the likely or eventual judgment sum which is important. If the plaintiff decides not to accept the amount offered and proceeds to trial, it is usually because he or she expects to obtain judgment for a greater sum of damages than was offered or, at the very least, is hopeful of doing so. If, for example, an offer of compromise is of $100,000 damages, a plaintiff who decides not to accept it hopes or expects to obtain, following the trial, judgment for an amount greater than that to obtain protection from an adverse order concerning the costs of the trial. A judgment sum as low as, say, $105,000 would justify the plaintiff's decision not to accept an offer of $100,000.