To a which level.

As by Nikolaev manufactured is on 1955 and offered a classification, as by this are having 5 levels of goitre as 0 is level and is norm.
0-thyroid is not determine.
1-As thyroid gland is not visible, but  feeling in palpation.
2-As thyroid gland i not visualizing in swallowing.
3-As for a calculation a visible goitre is neck contour changing.
4.-a visible goitre as deforming a neck.
5-As enlarged thyroid causes a compressing of a near organs.
As WHO IS later simplified this method and  selected are three levels of thyroid gland enlarging.
0 stage is without a goitre.
1 st stage as sizes of gland are raise for a sizes of distal phalanx of big finger a patient, as goitre is not visible,but finding is on palpation.
2 st stage is finding goitre  and in palpation and see with an eye.