Good day, service quality and customer retention are two different constructs but the former leads to the other. Other scholars may argue otherwise. You may measure service quality and customer retention independently. Then you can use multiple linear regression or logistic regression depending on the number of attributes used in measuring customer retention. I will recommend only one attribute so that you can use Multiple linear regression or Pearson moment correllation.

Hi， Najam Aneel，I‘ve worked on this toipic, and a manuscript is under reviewing. threre are sufficient measures and causal relationships for  service quality and customer satisfaction if you review related papers and literatures. But one thing is sure that there is a mediating factor tbetween the two variables- customer satisfaction.

Dear What can be the possible attributes of customer retention?

For the concept of service quality as well as it measurement you may look for SERVQUAL. A brief description of the tool, and pros and cons, you'll find in the Wiki.

You may try to capture customer retention by related measurements of loyality, commitment and advocacy. It depends, though, on your particular conceptualization of retention and its indicators.

http://en.wikipedia.org/wiki/SERVQUAL

The relationship model can be servqual _> customer relationship -> customer loyalty. SEM and PLS can be used as the model analysis.

Najam, I am in agreement with Thomas that service quality and customer retention are different constructs.  I have a contributed an article on service quality focusing also on SERVQUAL model and it works despite its criticism, so check both benefits and challenges with the model. But it also depends on the direction and concepts you want to apply as other have already pointed out. As customer retention, try to check a concept in the literature review focusing more on customer relationship to analysis models like RET , PERF in addition to what my fellow colleagues have pointed out. 

Although service quality and customer retention are different construct and could be measure through different ways i.e SERVQUAL for service quality, we have to have clear that if quality is recognized by customer it means that customer are satisfied and satisfaction is the base for customer retention

https://www.researchgate.net/publication/305627093_Exploring_the_Dimensions_of_Mobile_Banking_Service_Quality_Implications_for_the_Banking_Sector

Article Exploring the Dimensions of Mobile Banking Service Quality: ...