Schedule - Behind or Ahead

Recently after a discussion with my professor regarding the progress of the Dining Hall, I got to thinking about if they were on schedule or off schedule. At the beginning of the semester they were beginning to start the construction of the concrete wall that is seen in most of the photographs posted. Here almost 12 weeks or so later they are still working on pouring and constructing this wall. The construction schedule of a project is a heavily talked about issue in the classes I have taken so far in Building Construction. However, it just seems as though (on this construction project) that often times just walking by and looking at site may not be a good indicator of the progress that has taken place. Is the wall set-up on the schedule to take this long of a time? Are there other activities that are being completed that are not visible from a walk-through? I think this is interesting point and just wanted to make mention of it here. Just because a site looks like it hasn't been undergoing any progress, that isn't always the case.