Ginny's performance pizza is a small restaurant in san francisco that sells gluten-free pizzas. ginny's very tiny kitchen has barely enough room for the four ovens in which her workers bake the pizzas. ginny signed a lease obligating her to pay the rent for the four ovens for the next year. because of this, and because ginny's kitchen cannot fit more than four ovens, ginny cannot change the number of ovens she uses in her production of pizzas in the short run.
however, ginny's decision regarding how many workers to use can vary from week to week because her workers tend to be students. each monday, ginny lets them know how many workers she needs for each day of the week. in the short run, these workers are are inputs, and the inputs.

Reliability and validity reliability and validity are two important considerations that must be made with any type of data collection. reliability refers to the ability to consistently produce a given result. in the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways. unfortunately, being consistent in measurement does not necessarily mean that you have measured something correctly. to illustrate this concept, consider a kitchen scale that would be used to measure the weight of cereal that you eat in the morning. if the scale is not properly calibrated, it may consistently under- or overestimate the amount of cereal that’s being measured. while the scale is highly reliable in producing consistent results (e. g., the same amount of cereal poured onto the scale produces the same reading each time), those results are incorrect. this is where validity comes into play. validity refers to the extent to which a given instrument or tool accurately measures what it’s supposed to measure. while any valid measure is by necessity reliable, the reverse is not necessarily true. researchers strive to use instruments that are both highly reliable and valid.