Types: There are various types of survey research-descriptive,  evaluative, comparation, correlation, longitudinal, cross-sectional, cross-cllltural, etc. 

Descriptive  Survey:  In  the  survey approach, one can describe  in  a system facts and characteristics of the population. This type of  research  is  called survey. For example, "a  public opinion survey to assess eligible couples" attitude towards  family planning practices. This  is  an  example of a community survey to  establish  the needs  for a health education prograde. This type of  survey does not necessarily seek to explain relationship, compare groups, test hypothesis or make predictions. It  is  essentially exploratory in  nature. 

Correlation Survey: A descriptive study when  seeks relationship between variables  is called correlation survey. Here  the  researcher investigates the extent to which variations  in  one variable (e.g.  educational level) corresponds the  extent with  variations to  another variable  (e.g. perceived nutritional needs) based on  correlation coefficient. Therefore data are collected on more than one variables from the  same group of  subjects (e.g. educational level and perceived  nutritional needs) and  the magnitude relationship between variables are estimated. 

More  direct  is the  relationship, i.e.  higher the  educational level. higher is the perceived  nutritional needs, the  correlation coefficient value  r  is higher.  ' Here the  relationship is positive. The  r ranges  from  0  to +1  indicating positive relationship and 0  to  -1 showing negative relationship. Negative relationship shows when higher is  the value  of variable A lower  is  the value of variable B. For  example, when  the rate is higher  the amount of healing pus discharge is lower.