What if panel data is unbalanced?
An unbalanced panel (e.g., the second dataset above) is a dataset in which at least one panel member is not observed every period. Therefore, if an unbalanced panel contains N panel members and T periods, then the following strict inequality holds for the number of observations (n) in the dataset: n < N×T.
What is two-way fixed effect?
The two-way linear fixed effects regression ( 2FE ) has become a default method for estimating causal effects from panel data. Many applied researchers use the 2FE estimator to adjust for unobserved unit-specific and time-specific confounders at the same time.
Why the two-way fixed effects model is difficult to interpret?

Abstract. The two-way fixed effects (FE) model, an increasingly popular method for modeling time-series cross-section (TSCS) data, is substantively difficult to interpret because the model’s estimates are a complex amalgamation of variation in the over-time and cross-sectional effects.
Which of the following is a disadvantage of the fixed effects approach to estimating a panel data model?
Which of the following is a disadvantage of the fixed effects approach to estimating a panel model? The fixed effects approach can only capture cross-sectional heterogeneity and not temporal variation in the dependent variable. Correct!
How do you treat unbalanced panel data?
An unbalanced-panel is a dataset in which one panel member is not observed every period. To fix it, Run standard fixed effects models on your entire unbalanced data and get estimates.

What is the difference between one-way and two-way fixed effect model?
A one-way error model assumes λt=0 while a two-way error allows for λ∈R and that is the answer to the first question. The second question cannot be answered without more assumptions about the error structure or purpose of the study.
When should you use fixed effects?
Use fixed-effects (FE) whenever you are only interested in analyzing the impact of variables that vary over time. FE explore the relationship between predictor and outcome variables within an entity (country, person, company, etc.).
What is the difference between one way and two-way fixed effect model?
When would you use a fixed effects model?
What do fixed effects control for?
Fixed effects is a method of controlling for all variables, whether they’re observed or not, as long as they stay constant within some larger category.