8 6 , ▁and ▁holds ▁a ▁Post grad uate ▁Di pl oma ▁in ▁Education ▁from ▁the ▁National ▁Institute ▁of ▁Education , ▁which ▁he ▁obtained ▁in ▁ 1 9 8 7 . ▁He ▁obtained ▁a ▁Masters ▁in ▁Public ▁Administration ▁and ▁Management ▁from ▁N US ▁Business ▁School ▁and ▁Lee ▁K uan ▁Y ew ▁School ▁of ▁Public ▁Policy ▁in ▁ 2 0 1 3 . ▁ ▁Career ▁ ▁Education ▁Ye o ▁started ▁his ▁career ▁in ▁ 1 9 8 7 ▁as ▁a ▁teacher ▁at ▁N any ang ▁Junior ▁College , ▁and ▁in ▁ 1 9 9 1 , ▁he ▁became ▁a ▁Head ▁of ▁Department ▁at ▁Anderson ▁Second ary ▁School . ▁From ▁ 1 9 9 3 ▁to ▁ 1 9 9 6 , ▁he ▁was ▁a ▁Special ist ▁Ins pect or ▁for ▁Chinese ▁at ▁the ▁Ministry ▁of ▁Education . ▁ ▁Labour ▁Mov ement ▁ ▁In ▁ 1 9 9 7 , ▁he ▁joined ▁the ▁labour ▁movement ▁as ▁an ▁Executive ▁Secretary ▁for ▁the ▁Building ▁Const ruction ▁and ▁Tim ber ▁Indust ries ▁Emp loy ees ▁Union ▁( B AT U ). ▁In ▁ 2 0 0 1 , ▁he ▁moved ▁on ▁to ▁become ▁the ▁Executive ▁Secretary ▁for ▁Singapore ▁Indust rial ▁and ▁Services ▁Emp loy ees ▁Union ▁( SI SE U ). ▁In ▁ 2 0 0 7 , ▁he ▁became ▁the ▁Executive ▁Secretary ▁for ▁the ▁Am alg am ated ▁Union ▁of ▁Stat ut ory ▁Board ▁Emp loy ees ▁( AU SB E ). ▁ ▁In ▁January ▁ 2 0 1 4 , ▁Ye o ▁was ▁appointed ▁Ass istant