app/views/surveys/_multiple.html.erb
<div class="input">
<%= label_tag question.key, question.text %>
<ul class="usa-unstyled-list">
<%- question.choices.each do |choice| %>
<li class="radio">
<%- option_id = "#{question.key}-#{choice.value}" %>
<%= check_box_tag "survey[#{question.key}][]", choice.value, false, {id: option_id} %>
<%= label_tag option_id, choice.label %>
</li>
<%- end %>
</ul>
</div>