Las Vegas, Nev. — Several junior high students from New England were discussing recently how much more they like their school this year than last. Asked what made for the improvement, they chimed, ''We got a much better principal.''
These students recognize a fact that is drawing increased attention among educators: A good principal is an essential part of a successful school. Now, a small but growing number of school districts are tapping into a program that aims to help identify good candidates for the job.
The program, called the Assessment Center Project and developed by the National Association of Secondary School Principals (NASSP), uses written tests, play-acting exercises, and interviews to help determine whether educators leaning toward a career in school administration are suited to the task.
The goal is to give a school district an objective basis on which to judge administrative candidates - a great number of whom will be reviewed in coming years, as thousands of new principalships open up across the US.
The assessment project, based at NASSP headquarters in Reston, Va., operates in 20 locations around the United States and involves some 200 school districts. Since its inception in 1975, the program has assessed more than 1,500 aspiring administrators, graduate students, and principals.
Many educators feel the typical method of selecting school principals shows little respect for the job's importance. Too often, they say, the principal is chosen because he or she has been a good teacher - or a good coach - or has been politically astute in seeking a promotion.
''But a good teacher will not necessarily make a good principal,'' says Paul Hersey, NASSP project director. ''In too many cases the determining factor (in selection) has been an interview in which panel members have looked for a candidate like themselves. And that's fairly unscientific.''
Drawing on similar programs in the military and business, the NASSP has compiled a list of 12 characteristics of a good principal. These include such broad skills as judgment, organization, sensitivity, speaking ability, and decisiveness.
Trained assessors who are principals or hold district posts in school administration use the list of qualities to evaluate participants during a two-day session. Reading materials or classes are often suggested to help address weaknesses.
At the NASSP's convention here in Las Vegas recently, several school administrators acted out a typical assessment center exercise. Their assignment - to select from among six choices the best candidate for an assistant principalship - allowed observers to gauge participants' oral skills, perception , and ability to work with others.
But does the assessment concept really work? For Mary Anne Stro, who was named principal of Montgomery Junior High School in San Diego County, Calif., shortly after taking part in an assessment session, the exercises were an important part of her professional preparation. ''I realize now the exercises were very realistic,'' she says.
Results of a three-year study completed in 1981 by a Michigan State University research team indicate a high correlation between a participant's performance at the assessment center and in an administrative post. In addition, the study found that the criteria used to judge participants accurately reflected the basic skills of a good principal.
Despite these findings, not everyone sees the assessment center as an unmitigated success. Leonard Pellicer, department chairman for education leadership and policy at the University of South Carolina and a trained project assessor, fears the project is being sold as a ''magic potion'' that can solve a district's needs for good administrative leadership.
But identifying potential principals, he says, is not a district's most difficult task. ''The real problem is that the supply of prospective principals is not going to be there to choose from.''
In addition, several participants who are already principals say the sessions offer little they hadn't already learned. But among those contacted by the Monitor who went on to become principals the feeling is very positive - though they sometimes say competition among participants or a feeling that assessors seek preconceived ''right'' responses hinders the process.