Web surveys have several advantages: low data collection costs, simplified and fast field operations. They also allow to expose subjects to different stimuli.
However, coverage is a major reason of concern, with the exception of studies targeted to specialized - ICT literate - populations.

When considering general population surveys, is it possible to take advantage of web questionnaires while using a probability-based sample with limited problems of coverage? If so, what are the main methodological and operational implications?
Trying to provide some answers to these questions, the paper discusses the main evidences from a mixed-mode survey carried out on young households in Trento (Italy, Spring 2010) with a 90% response rate (816 interviews).

The main focus of this study was on childcare and nursery schools. The survey was also intended as a methodological experiment, in order to explore alternatives to the (sole) CATI surveys, because of coverage problems of the latter.
Sampling and contact phases (population registers as a frame and mail contacts respectively) were distinguished from data collection modes: CAWI (60% of the interviews) + CATI (27%) + PAPI (13%).
Immigrant parents were of special interest to the research. They were oversampled. Contact materials were delivered in 12 different languages. CATI and PAPI interviewers covered the same set of languages.

The survey reasonably succeeded in balancing the production of good quality data - in terms of good coverage and use of a probabilistic sample - with reasonable costs, thanks to the possibility to use CAWI and CATI wherever possible.