I don't think that's right. Only the specific funds (e.g. the Vanguard 500 Index Fund (VFINX)) that say they track the indices do that (and generally charge a lower 'management' fee). Most funds (e.g. the Vanguard Capital Value Fund (VCVLX)) try to beat the indices, charge higher fees and have a range of things they are allowed to buy. There's the control.
I don't think that's right. Only the specific funds (e.g. the Vanguard 500 Index Fund (VFINX)) that say they track the indices do that (and generally charge a lower 'management' fee). Most funds (e.g. the Vanguard Capital Value Fund (VCVLX)) try to beat the indices, charge higher fees and have a range of things they are allowed to buy. There's the control.