Convenient notation 口 Fixed Effects Yt=01+x1β+ct Individual specific constant terms 口 Random effects Yt=X1β+ct+u Compound c"disturbance;error componentsConvenient Notation  Fixed Effects  Random Effects it i it it y = + +   x Individual specific constant terms. it it it i y = + + u x  Compound (“composed”) disturbance; “error components