I am now retired, but I spent over 30 years working in a large US corporation. In the course of my career, my company went through all of the corporate management fads that swept American businesses, one of which was the infatuation with "mission statements" that began not too long after I came on board in 1983. This is not the forum in which to discuss the pros and cons of the mission statement culture; like most corporate fads, it has its good and (mostly) bad points, and is only as effective as the people who use it. I only bring it up because...believe it or not, my parish has a "Mission Statement." I won't repeat it here, but it's somewhat verbose, running fifty-five words, and is stated as the "mission" of "we, the members of St. XYZ parish." That seems a bit exaggerated, since like most "modern" parishes, all the work not done by the priests and deacons and paid staff is done by about five or six percent of the registered parishioners. Another fifteen to twenty percent actually show up for Mass at least once a week, and the rest are phantoms except possibly at Christmas or Easter, when they roll in with their guilt offerings (much appreciated, but where were you the rest of the year?) and clog up the church and the parking lot for the rest of us. :) In any event, the idea of "we, the members" issuing the mission statement is, in my view, just silly, and is one of the regrettable results of the attempt by the Second Vatican Council to de-emphasize the Church hierarchy. As far as I can tell from studying the history of the past fifty years, (admittedly just the blink of an eye in the overall 2,000-year history of the Church), we likely would have been a lot better off if they had left the hierarchy alone and concentrated more on evangelizing and saving souls than on trying to make lay people feel more important. Which leads me back to my real point.
The notion that a Catholic parish needs a spiffy "mission statement" at all simply bewilders me. This is not a business. It is not a public service organization, despite all the charitable and community works we do--those are some results of what we do, not the essence. Every parish is simply a place where we gather to worship the God of the universe and to thank him for sending his Son to die for us, that we might have the chance to spend eternity with him in Heaven, and where we can receive the Sacraments established by Christ as channels of sanctifying grace to help us along the way. So the "mission statement" ought to be very simple: "To bring souls to Jesus Christ and thus to eternal salvation." There you have it, in eleven words that probably could be shortened even more. Anything else is redundant.
Laudator Jesus Christus!