Some writers become confused when they must make a possessive of singular nouns that already end in s. As usual, you make the possessive by adding ’s to the word; however, some writers and editors argue that the two s’ are redundant and that therefore you can eliminate the second s, ending up with the s’. That is, they argue that there is really no need to include an s after the apostrophe, since the apostrophe already tells readers that the word is possessive. Others argue that you should drop the final s only on words of several syllables but retain it on short words. Since there is no agreement on this difficult problem, you must make your own choice. However, regardless of which option you choose, do remember to be consistent.