My Android program using GPS is very inaccurate

Question

I have made a program using GPS and its Latitude and Longitude are about 8 miles off.

I thought it may be because I am inside but when I use google maps on my phone, it shows me at my house.

Any idea why this may be?

Code below:

public class Clue extends Activity {

public static double latitude;
public static double longitude;
LocationManager lm;
LocationListener ll;
Location location;

      /** Called when the activity is first created. */
  @Override
     public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
  setContentView(R.layout.blah);

  Criteria criteria = new Criteria();
  criteria.setAccuracy(Criteria.ACCURACY_FINE);

  lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
  ll = new MyLocationListener()}

private boolean getLoc() {
location = getLocation(); 

   longitude = location.getLongitude();
   latitude = location.getLatitude();
return inCorrectPlace(params);
}


    private Location getLocation() {
  lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);   
  return lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
}
}

I have stripped out irrelevant code, all help will be appreciated.