• Null Hypothesis
• Damaged Building Hypothesis • Aesthetic Hypothesis
• Affected Health Hypothesis
• That Which is Visible is Mold Hypothesis • An Example
A similar approach to gaining knowledge is shared by all scientific disciplines. The scientific method involves observing empirical evidence and drawing inferences from it. One school of thought holds that sampling can only disprove a hypothesis, and an inspector can never prove a cause-effect relationship. An alternative understanding of the basis of scientific knowledge is that all inspectors begin with a set of prior beliefs or assumptions. For example, an inspector may begin an examination of a building with an underlying assumption that there exist numerous undiscovered deficiencies in the building. Progress is made as hypotheses (based upon prior beliefs) are tested by collecting data, which either supports or refutes the hypotheses and underlying beliefs.
Before any sampling takes place, an inspector should develop a set of hypotheses that address the concerns of the inspector’s client. A hypothesis is a proposition set forth as an explanation for the specific observation or condition experienced. A hypothesis is often used to guide the inspection (a working hypothesis) and can be accepted as highly probable in the light of established facts.
Hypotheses concerning the suspected role of fungal (mold) exposure on adverse effects should be developed BEFORE any mold sampling takes place. The inspector and client should agree to the hypotheses and agree upon how they should be addressed.
The inspector needs to gather information, develop hypotheses, test the hypotheses, and make recommendations based upon all available information gathered.
Gather Information
Gathering information involves asking the client about their concerns about mold; the reasons why they are requesting a mold inspection; and what relevant information they intend to receive from an inspection. Setting expectations with the client is part of this information gathering process.
There are generally three (3) types of CONCERNS clients may express about mold growth in a building:
1) client is concerned about the potential health effects of exposure to fungi and their byproducts;
2) client is concerned about the effect of mold contamination on the structural integrity of the building; and
3) client is concerned about the negative aesthetic effects fungi can produce both visually and on the human olfactory systems. 9
Although the issue of whether exposure to indoor fungi causes adverse health effects is
controversial, there is no doubt that a seriously mold-contaminated building can suffer structural damage, and that a foul-smelling, fungus-filled building is aesthetically unpleasing.
Controversies about health effects aside, the latter two concerns are sufficient to merit a complete mold inspection and remediation when an environment is found to have fungal contamination.
People who have concerns about structural damage or the aesthetic effects of indoor fungi should seek the services from a certified mold inspector. People who have concerns about health effects of mold exposure should seek the counsel of a health care professional.
There are generally eight (8) questions that can be answered by a visual examination and mold sampling of a building:
1) Is there water intrusion in the building?
2) Are there water damaged components in the building? 3) Are there musty, moldy odors in the building?
4) Is there any visible apparent mold? 5) Is that which is visible actually mold?
6) Are there indications of hidden mold growth? 7) Are there conditions conducive to mold growth? 8) What should be done if mold growth is discovered?
To address these concerns, hypotheses, and questions accurately, a visual examination must be performed to a standard, mold samples must be taken according to procedures, laboratory
analysis must be included, and proper documentation must be made. Proper collection, handling, and documentation of a mold sample are all required for a conclusive, credible report. All
inspection procedures should be followed carefully and precisely. Poor handling can lead to mistakes, errors, and liability exposure.
Develop Hypotheses
There are generally four (4) types of HYPOTHESES about fungi in an indoor environment that can be developed by the inspector and the client:
1) there is no mold growth in the building (null hypothesis);
2) health is being affected by mold exposure (health affected hypothesis);
3) structural damage is caused by mold growth in the building (damaged building hypothesis); and
4) a musty odor indicates mold growth (aesthetic hypothesis). Null Hypothesis
An inspector should approach a mold inspection without bias towards finding mold. It is
reasonable to assume that a building does not have a mold growth problem. If the client does not have any concerns, then the inspector should assume that there are no mold growth problems in the building (null hypothesis). The inspector should approach the mold inspection with an
assumption that there is no mold growth in the building should be made prior to performing a mold inspection. That way, if an actual mold problem is found at the building, it will be
unexpected. Legally, it is a stronger argument that a mold inspector initiated a mold inspection without bias, without a presumption that a mold problem existed in a building. If your client does not express a particular concern about mold in the building, then make the null hypothesis, assume that there is no mold in the building prior to performing the inspection. 12