Eugene Kridler to Roger B. Clapp 
January 1970 
This belt, Roger, contains answers and comments relative to the questions 
you asked in your letter of November 19th, 1969* 
Your first question on Nihoa-Necker - you say ”in this report for both 
Nihoa and Necker, that is the March-April 1969 report, you refer to the trip 
taken in 1968 as having been made in September.” You’re talking about two 
different trip reports so according to the tenor of your first question I 
assume you’re talking about the fall trip of 1968. I had listed the Necker 
dates as 28-29 August and gave Nihoa as 24 and 27 of September. The latter 
is an error. August is the correct month for 1968. We were on Nihoa from 
August 1 24 th through August 27 and then on Necker August 28 th through 
& 
August 29th, so that should settle that. 
Now, question two. What is the significance of your class data 
system A,B,C,D, so forth? We started classifying our data as to what we 
figured was the reliability. This then will give other people that follow 
or others that read our reports some idea of whether this was just an 
educated guess or whether it is very good, firm data, so in essence it’s as 
follows. 
Class A data is essentially a head count with very little room for 
error. Most of the Class A data will really pertain to all areas like 
Pearl and Hermes and some of the others where we actually went out and 
counted almost every individual. 
Class B data - are all data which are + and - 20 % error with a 95 % 
confidence level. 
Class C data would be + or - 50 % and a 95 % confidence limit. 
Class D data is essentially an educated guess. 
