Five research studies dealing with spelling achievement in New Zealand schools have been conducted; these include dictated-word spelling tests, written language studies, and achievement data collections of 20,000 students. Several conclusions emerge from an examination of this research: spelling achievement studies should be based on samples of written language, should concentrate on in-depth analysis of written language samples, should test extensively, and should employ appropriate statistical techniques rather than simply using mean scores and percentages; tests should sample broadly among pupils and words; and tests should refrain from using studies not originally designed to investigate changing levels of performance to support a thesis of changing levels. It appears that factors outside the school have much to do with spelling achievement, although little has been done to validate current teaching approaches. The apparent test score declines could be explained by changed teaching emphases as well as by problems with research methodology. Data is lacking to make reliable generalizations about changing levels of achievement over time. (DF)